Temperature conversion: Difference between revisions

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There are quite a number of temperature scales. For this task we will concentrate on 4 of the perhaps best-known ones: [[wp:Kelvin|Kelvin]], [[wp:Degree Celsius|Celsius]], [[wp:Fahrenheit|Fahrenheit]] and [[wp:Degree Rankine|Rankine]].
There are quite a number of temperature scales. <br>
For this task we will concentrate on 4 of the perhaps best-known ones: [[wp:Kelvin|Kelvin]], [[wp:Degree Celsius|Celsius]], [[wp:Fahrenheit|Fahrenheit]] and [[wp:Degree Rankine|Rankine]].


The Celsius and Kelvin scales have the same magnitude, but different null points.
The Celsius and Kelvin scales have the same magnitude, but different null points.
Line 8: Line 10:
:0 kelvin is absolute zero.
:0 kelvin is absolute zero.


The Fahrenheit and Rankine scales also have the same magnitude, but different null points.
The Fahrenheit and Rankine scales also have the same magnitude,
but different null points.


:0 degrees Fahrenheit corresponds to '''459.67''' degrees Rankine.
:0 degrees Fahrenheit corresponds to '''459.67''' degrees Rankine.
Line 15: Line 18:
The Celsius/Kelvin and Fahrenheit/Rankine scales have a ratio of '''5 : 9'''.
The Celsius/Kelvin and Fahrenheit/Rankine scales have a ratio of '''5 : 9'''.


Write code that accepts a value of kelvin, converts it to values on the three other scales and prints the result. For instance:
Write code that accepts a value of kelvin, converts it
to values on the three other scales and prints the result.

For instance:
<pre>
<pre>
K 21.00
K 21.00
Line 261: Line 267:
END
END
</lang>
</lang>
{{out}}
Output:
<pre>
<pre>
Kelvin degrees (>=0): 21
Kelvin degrees (>=0): 21
Line 270: Line 276:
R = 37.80
R = 37.80
</pre>
</pre>

=={{header|Bracmat}}==
=={{header|Bracmat}}==
<lang bracmat>( ( rational2fixedpoint
<lang bracmat>( ( rational2fixedpoint
Line 317: Line 324:
& done!
& done!
)</lang>
)</lang>
{{out}}
Output:
<pre>Enter Kelvin temperature:21.00
<pre>Enter Kelvin temperature:21.00
21.00 K
21.00 K
Line 324: Line 331:
37.80 °Ra
37.80 °Ra
-201.72 °Ré</pre>
-201.72 °Ré</pre>

=={{header|C}}==
=={{header|C}}==
<lang c>#include <stdio.h>
<lang c>#include <stdio.h>
Line 412: Line 420:
//--------------------------------------------------------------------------------------------------
//--------------------------------------------------------------------------------------------------
</lang>
</lang>
{{out}}
Output:
<pre>
<pre>
Enter the temperature in Kelvin to convert: 373.15
Enter the temperature in Kelvin to convert: 373.15
Line 517: Line 525:
</lang>
</lang>


{{out}}
Interpreter output:

<pre>
<pre>
* (temperature-conversion)
* (temperature-conversion)
Line 527: Line 534:
NIL
NIL
</pre>
</pre>



=={{header|D}}==
=={{header|D}}==
Line 1,466: Line 1,472:
Test:
Test:
<lang PicoLisp>(convertKelvin 21.0)</lang>
<lang PicoLisp>(convertKelvin 21.0)</lang>
{{out}}
Output:
<pre>K 21.00
<pre>K 21.00
C -252.15
C -252.15
Line 1,621: Line 1,627:
End;
End;
End;</lang>
End;</lang>
{{out}}
Output (sample):
<pre>
<pre>
21.00 KELVIN -> -252.15 CELSIUS
21.00 KELVIN -> -252.15 CELSIUS
Line 1,908: Line 1,914:
/*──────────────────────────────────SERR subroutine─────────────────────*/
/*──────────────────────────────────SERR subroutine─────────────────────*/
serr: say; say '***error!***'; say; say arg(1); say; exit 13</lang>
serr: say; say '***error!***'; say; say arg(1); say; exit 13</lang>
'''output''' when using the input of: <tt> -40C, 0 c (water freezes), 37C (body temp), 100 C (water boils), 21 degrees Kelvin, 0K (outer space?) </tt>
{{out}} when using the input of: <tt> -40C, 0 c (water freezes), 37C (body temp), 100 C (water boils), 21 degrees Kelvin, 0K (outer space?) </tt>
<pre>
<pre>
───────────────────────────────────────────────── -40C
───────────────────────────────────────────────── -40C
Line 2,015: Line 2,021:
end</lang>
end</lang>
Converts all eight scales to any other scale, by means of method_missing. Usage:
Converts all eight scales to any other scale, by means of method_missing.

Usage:
<lang ruby>TempConvert.kelvin_to_celsius 100 #=> -173.15
<lang ruby>TempConvert.kelvin_to_celsius 100 #=> -173.15
TempConvert.kelvin_to_fahrenheit 100 #=> -279.67
TempConvert.kelvin_to_fahrenheit 100 #=> -279.67
Line 2,027: Line 2,035:
TempConvert.newton_to_fahrenheit 100 #=> 577.45
TempConvert.newton_to_fahrenheit 100 #=> 577.45
# All 64 combinations possible</lang>
# All 64 combinations possible</lang>

=={{header|Run BASIC}}==
=={{header|Run BASIC}}==
<lang runbasic>[loop]
<lang runbasic>[loop]
Line 2,179: Line 2,188:
100 PRINT r; " Degrees Rankine"
100 PRINT r; " Degrees Rankine"
110 GO TO 20</lang>
110 GO TO 20</lang>

{{omit from|Lilypond}}

Revision as of 19:55, 7 November 2014

Task
Temperature conversion
You are encouraged to solve this task according to the task description, using any language you may know.

There are quite a number of temperature scales.
For this task we will concentrate on 4 of the perhaps best-known ones: Kelvin, Celsius, Fahrenheit and Rankine.

The Celsius and Kelvin scales have the same magnitude, but different null points.

0 degrees Celsius corresponds to 273.15 kelvin.
0 kelvin is absolute zero.

The Fahrenheit and Rankine scales also have the same magnitude, but different null points.

0 degrees Fahrenheit corresponds to 459.67 degrees Rankine.
0 degrees Rankine is absolute zero.

The Celsius/Kelvin and Fahrenheit/Rankine scales have a ratio of 5 : 9.

Write code that accepts a value of kelvin, converts it to values on the three other scales and prints the result.

For instance:

K  21.00

C  -252.15

F  -421.87

R  37.80

Ada

<lang Ada>with Ada.Float_Text_IO, Ada.Text_IO; use Ada.Float_Text_IO, Ada.Text_IO;

procedure Temperatur_Conversion is

  K: Float;
  function C return Float is (K - 273.15);
  function F return Float is (K * 1.8 - 459.67);
  function R return Float is (K * 1.8);

begin

  Get(K); New_Line;                                           -- Format 
  Put("K: "); Put(K, Fore => 4, Aft => 2, Exp => 0); New_Line;-- K: dddd.dd
  Put("C: "); Put(C, Fore => 4, Aft => 2, Exp => 0); New_Line;-- C: dddd.dd
  Put("F: "); Put(F, Fore => 4, Aft => 2, Exp => 0); New_Line;-- F: dddd.dd
  Put("R: "); Put(R, Fore => 4, Aft => 2, Exp => 0); New_Line;-- R: dddd.dd

end;</lang>

Output:
21.0

K:   21.00
C: -252.15
F: -421.87
R:   37.80

Aime

<lang aime>void show(integer symbol, real temperature) {

   o_form("%c /d2p2w8/\n", symbol, temperature);

}

integer main(void) {

   real k;
   k = atof(argv(1));
   show('K', k);
   show('C', k - 273.15);
   show('F', k * 1.8 - 459.67);
   show('R', k * 1.8);
   return 0;

}</lang>

Output:
aime$ aime -a tmp/tconvert 300
K   300   
C    26.85
F    80.32
R   540

AutoHotkey

<lang AutoHotkey>MsgBox, % "Kelvin:`t`t 21.00 K`n"

       . "Celsius:`t`t" kelvinToCelsius(21) " C`n"
       . "Fahrenheit:`t" kelvinToFahrenheit(21) " F`n"
       . "Rankine:`t`t" kelvinToRankine(21) " R`n"

kelvinToCelsius(k) {

   return, round(k - 273.15, 2)

} kelvinToFahrenheit(k) {

   return, round(k * 1.8 - 459.67, 2)

} kelvinToRankine(k) {

   return, round(k * 1.8, 2)

}</lang>

Output:
Kelvin:          21.00 K
Celsius:       -252.15 C
Fahrenheit:    -421.87 F
Rankine:         37.80 R

AWK

"Interactive" version, reading from stdin only: <lang AWK># syntax: AWK -f TEMPERATURE_CONVERSION.AWK BEGIN {

   while (1) {
     printf("\nKelvin degrees? ")
     getline K
     if (K ~ /^$/) {
       break
     }
     if (K < 0) {
       print("K must be > 0")
       continue
     }
     printf("K = %.2f\n",K)
     printf("C = %.2f\n",K - 273.15)
     printf("F = %.2f\n",K * 1.8 - 459.67)
     printf("R = %.2f\n",K * 1.8)
   }
   exit(0)

}</lang>

"Regular" version, reading from input-file(s).
With no such file, or "-" as filename, reading from stdin:

Works with: gawk

BEGINFILE is a gawk-extension

<lang AWK># usage: gawk -f temperature_conversion.awk input.txt -

BEGIN { print("# Temperature conversion\n") } BEGINFILE { print "# reading", FILENAME

           if( FILENAME=="-" ) print "# Please enter temperature values in K:\n"
         }

!NF { exit }

         { print "Input:" $0 }     

$1<0 { print("K must be >= 0\n"); next }

         { K = 0+$1
           printf("K = %8.2f Kelvin degrees\n",K)
           printf("C = %8.2f\n",  K - 273.15)
           printf("F = %8.2f\n",  K * 1.8 - 459.67)
           printf("R = %8.2f\n\n",K * 1.8)
         }

END { print("# Bye.") } </lang>

Input:

the numeric value of the first word in each line is used as input for the conversion

-1
absolute
184
273.15 ice melts
310x
373.15 water boils
1941 Titanium melts

So, "absolute" has a value of 0, and 310x is just 310.

After that file is read and processed, values are read from stdin.
Here entering "333" by hand, and then stopping with an empty input.

Output:
# Temperature conversion

# reading input.txt
Input:-1
K must be >= 0

Input:absolute
K =     0.00 Kelvin degrees
C =  -273.15
F =  -459.67
R =     0.00

Input:184
K =   184.00 Kelvin degrees
C =   -89.15
F =  -128.47
R =   331.20

Input:273.15 ice melts
K =   273.15 Kelvin degrees
C =     0.00
F =    32.00
R =   491.67

Input:310x
K =   310.00 Kelvin degrees
C =    36.85
F =    98.33
R =   558.00

Input:373.15 water boils
K =   373.15 Kelvin degrees
C =   100.00
F =   212.00
R =   671.67

Input:1941 Titanium melts
K =  1941.00 Kelvin degrees
C =  1667.85
F =  3034.13
R =  3493.80

# reading -
# Please enter temperature values in K:

Input:333
K =   333.00 Kelvin degrees
C =    59.85
F =   139.73
R =   599.40

# Bye.

BASIC

<lang basic> 10 REM TRANSLATION OF AWK VERSION 20 INPUT "KELVIN DEGREES",K 30 IF K <= 0 THEN END: REM A VALUE OF ZERO OR LESS WILL END PROGRAM 40 LET C = K - 273.15 50 LET F = K * 1.8 - 459.67 60 LET R = K * 1.8 70 PRINT K; " KELVIN IS EQUIVALENT TO" 80 PRINT C; " DEGREES CELSIUS" 90 PRINT F; " DEGREES FAHRENHEIT" 100 PRINT R; " DEGREES RANKINE" 110 GOTO 20 </lang>

BASIC256

<lang basic256> do

 print "Kelvin degrees (>=0): ";
 input K
 until K>=0

print "K = " + string(K) print "C = " + string(K - 273.15) print "F = " + string(K * 1.8 - 459.67) print "R = " + string(K * 1.8) </lang>

BBC BASIC

<lang bbcbasic> REPEAT

 INPUT "Kelvin degrees (>=0): " K

UNTIL K>=0 @%=&20208 PRINT '"K = " K PRINT "C = " K - 273.15 PRINT "F = " K * 1.8 - 459.67 PRINT "R = " K * 1.8 END </lang>

Output:
Kelvin degrees (>=0): 21

K =    21.00
C =  -252.15
F =  -421.87
R =    37.80

Bracmat

<lang bracmat>( ( rational2fixedpoint

 =   minus fixedpointnumber number decimals
   .   !arg:(#?number.~<0:~/#?decimals)
     & ( !number:0&"0.0"
       |     ( !number:>0&
             | -1*!number:?number&"-"
             )
           : ?minus
         & !number+1/2*10^(-1*!decimals):?number
         & !minus div$(!number.1) ".":?fixedpointnumber
         &   whl
           ' ( !decimals+-1:~<0:?decimals
             &     !fixedpointnumber
                   div$(mod$(!number.1)*10:?number.1)
               : ?fixedpointnumber
             )
         & str$!fixedpointnumber
       )
 )

& ( fixedpoint2rational

 =   integerpart fractionalpart decimals
   .   @( !arg
        :   #?integerpart
            ( "." ?fractionalpart
            | &0:?fractionalpart
            )
        )
     & @(!fractionalpart:? #?fractionalpart [?decimals)
     &   !integerpart
       +   (!integerpart:<0&-1|1)
         * 10^(-1*!decimals)
         * !fractionalpart
 )

& whl

 ' ( put$"Enter Kelvin temperature:"
   & fixedpoint2rational$(get'(,STR)):?kelvin
   & !kelvin+-27315/100:?celcius
   & (degree=.str$(chu$(x2d$b0) !arg))
   & out$(rational2fixedpoint$(!kelvin.2) K)
   & out$(rational2fixedpoint$(!celcius.2) degree$C)
   & out$(rational2fixedpoint$(!celcius*9/5+32.2) degree$F)
   & out$(rational2fixedpoint$(!kelvin*9/5.2) degree$Ra)
   & out$(rational2fixedpoint$(!celcius*4/5.2) degree$Ré)
   )

& done! )</lang>

Output:
Enter Kelvin temperature:21.00
21.00 K
-252.15 °C
-421.87 °F
37.80 °Ra
-201.72 °Ré

C

<lang c>#include <stdio.h>

  1. include <stdlib.h>

double kelvinToCelsius(double k){

   return k - 273.15;

}

double kelvinToFahrenheit(double k){

   return k * 1.8 - 459.67;

}

double kelvinToRankine(double k){

   return k * 1.8;

} void convertKelvin(double kelvin) {

   printf("K %.2f\n", kelvin);
   printf("C %.2f\n", kelvinToCelsius(kelvin));
   printf("F %.2f\n", kelvinToFahrenheit(kelvin));
   printf("R %.2f", kelvinToRankine(kelvin));

}

int main(int argc, const char * argv[]) {

   if (argc > 1) {
       double kelvin = atof(argv[1]);
       convertKelvin(kelvin);
   }
   return 0;

}</lang>

C++

<lang cpp>

  1. include <iostream>
  2. include <iomanip>

//-------------------------------------------------------------------------------------------------- using namespace std;

//-------------------------------------------------------------------------------------------------- class converter { public:

   converter() : KTC( 273.15f ), KTDel( 3.0f / 2.0f ), KTF( 9.0f / 5.0f ), KTNew( 33.0f / 100.0f ),

KTRank( 9.0f / 5.0f ), KTRe( 4.0f / 5.0f ), KTRom( 21.0f / 40.0f ) {}

   void convert( float kelvin )
   {

float cel = kelvin - KTC, del = ( 373.15f - kelvin ) * KTDel, fah = kelvin * KTF - 459.67f, net = cel * KTNew, rnk = kelvin * KTRank, rea = cel * KTRe, rom = cel * KTRom + 7.5f;

cout << endl << left << "TEMPERATURES:" << endl << "===============" << endl << setw( 13 ) << "CELSIUS:" << cel << endl << setw( 13 ) << "DELISLE:" << del << endl << setw( 13 ) << "FAHRENHEIT:" << fah << endl << setw( 13 ) << "KELVIN:" << kelvin << endl << setw( 13 ) << "NEWTON:" << net << endl << setw( 13 ) << "RANKINE:" << rnk << endl << setw( 13 ) << "REAUMUR:" << rea << endl << setw( 13 ) << "ROMER:" << rom << endl << endl << endl; } private:

   const float KTRank, KTC, KTF, KTRe, KTDel, KTNew, KTRom;

}; //-------------------------------------------------------------------------------------------------- int main( int argc, char* argv[] ) {

   converter con;
   float k;
   while( true )
   {

cout << "Enter the temperature in Kelvin to convert: "; cin >> k; con.convert( k ); system( "pause" ); system( "cls" );

   }
   return 0;

} //-------------------------------------------------------------------------------------------------- </lang>

Output:
Enter the temperature in Kelvin to convert: 373.15

TEMPERATURES:
===============
CELSIUS:     100
DELISLE:     0
FAHRENHEIT:  212
KELVIN:      373.15
NEWTON:      33
RANKINE:     671.67
REAUMUR:     80
ROMER:       60

Clojure

Translation of: Common Lisp

<lang clojure>(defn to-celsius [k]

 (- k 273.15))

(defn to-fahrenheit [k]

 (- (* k 1.8) 459.67))

(defn to-rankine [k]

 (* k 1.8))

(defn temperature-conversion [k]

 (if (number? k) 
   (format "Celsius: %.2f Fahrenheit: %.2f Rankine: %.2f" 
     (to-celsius k) (to-fahrenheit k) (to-rankine k)) 
   (format "Error: Non-numeric value entered.")))</lang>
Output:
user=> (temperature-conversion 21.0)
"Celsius: -252.15 Fahrenheit: -421.87 Rankine: 37.80"

COBOL

Works with: Visual COBOL

<lang cobol> IDENTIFICATION DIVISION.

      PROGRAM-ID. temp-conversion.
      
      DATA DIVISION.
      WORKING-STORAGE SECTION.
      78  Kelvin-Rankine-Ratio    VALUE 0.5556. *> 5 / 9 to 4 d.p.
      78  Kelvin-Celsius-Diff     VALUE 273.15.
      78  Rankine-Fahrenheit-Diff VALUE 459.67.
      
      01  temp-kelvin             PIC S9(8)V99.
      01  temp-rankine            PIC S9(8)V99.
      
      01  kelvin                  PIC -(7)9.99.
      01  celsius                 PIC -(7)9.99.
      01  rankine                 PIC -(7)9.99.
      01  fahrenheit              PIC -(7)9.99.
      
      PROCEDURE DIVISION.
          DISPLAY "Enter a temperature in Kelvin to convert: " NO ADVANCING
          ACCEPT temp-kelvin
      
          MOVE temp-kelvin TO kelvin
          DISPLAY "K " kelvin
          
          SUBTRACT Kelvin-Celsius-Diff FROM temp-kelvin GIVING celsius
          DISPLAY "C " celsius
          
          DIVIDE temp-kelvin BY Kelvin-Rankine-Ratio
              GIVING temp-rankine, rankine
          SUBTRACT Rankine-Fahrenheit-Diff FROM temp-rankine GIVING fahrenheit
          
          DISPLAY "F " fahrenheit
          DISPLAY "R " rankine
      
          GOBACK
          .</lang>
Output:
Enter a temperature in Kelvin to convert: 21
K       21.00
C     -252.15
F     -421.88
R       37.79

Common Lisp

Three functions define the necessary conversion formulas. A fancy format string is used to print these values.

<lang lisp> (defun to-celsius (k)

 (- k 273.15))

(defun to-fahrenheit (k)

 (- (* k 1.8) 459.67))

(defun to-rankine (k)

 (* k 1.8))

(defun temperature-conversion ()

 (let ((k (read))) 
   (if (numberp k) 
     (format t "Celsius: ~d~%Fahrenheit: ~d~%Rankine: ~d~%" 
       (to-celsius k) (to-fahrenheit k) (to-rankine k)) 
     (format t "Error: Non-numeric value entered."))))

</lang>

Output:
* (temperature-conversion)
21
Celsius: -252.15
Fahrenheit: -421.87003
Rankine: 37.8
NIL

D

<lang d>double kelvinToCelsius(in double k) pure nothrow @safe {

   return k - 273.15;

}

double kelvinToFahrenheit(in double k) pure nothrow @safe {

   return k * 1.8 - 459.67;

}

double kelvinToRankine(in double k) pure nothrow @safe {

   return k * 1.8;

}

unittest {

   import std.math: approxEqual;
   assert(approxEqual(kelvinToCelsius(21.0), -252.15));
   assert(approxEqual(kelvinToFahrenheit(21.0), -421.87));
   assert(approxEqual(kelvinToRankine(21.0), 37.8));

}

void main(string[] args) {

   import std.stdio, std.conv, std.string;
   if (args.length == 2 && isNumeric(args[1])) {
       immutable kelvin = to!double(args[1]);
       if (kelvin >= 0) {
           writefln("K  %2.2f", kelvin);
           writefln("C  %2.2f", kelvinToCelsius(kelvin));
           writefln("F  %2.2f", kelvinToFahrenheit(kelvin));
           writefln("R  %2.2f", kelvinToRankine(kelvin));
       } else
           writefln("%2.2f K is below absolute zero", kelvin);
   }

}</lang>

Output:
K  21.00

C  -252.15

F  -421.87

R  37.80

Delphi

<lang delphi> program Temperature;

{$APPTYPE CONSOLE}

uses

 SysUtils;

type

 TTemp = class
 private
   fCelsius, fFahrenheit, fRankine: double;
 public
   constructor Create(aKelvin: double);
   property AsCelsius: double read fCelsius;
   property AsFahrenheit: double read fFahrenheit;
   property AsRankine: double read fRankine;
 end;
 { TTemp }

constructor TTemp.Create(aKelvin: double); begin

 fCelsius := aKelvin - 273.15;
 fRankine := aKelvin * 9 / 5;
 fFahrenheit := fRankine - 459.67;

end;

var

 kelvin: double;
 temp: TTemp;

begin

 write('Kelvin: ');
 readln(kelvin);
 temp := TTemp.Create(kelvin);
 writeln(Format('Celsius: %.2f', [temp.AsCelsius]));
 writeln(Format('Fahrenheit: %.2f', [temp.AsFahrenheit]));
 writeln(Format('Rankine: %.2f', [temp.AsRankine]));
 temp.Free;
 readln;

end. </lang>

Output:
Kelvin: 21.00
Celsius: -252.15
F: -421.87
R: 37.80

Erlang

<lang erlang>% Implemented by Arjun Sunel -module(temp_conv). -export([main/0]).

main() -> conversion(21).

conversion(T) -> io:format("\nK : ~p\n\n",[f(T)]), io:format("C : ~p \n\n",[f(T - 273.15)]), io:format("F : ~p\n\n",[f(T * 1.8 - 459.67)]), io:format("R : ~p\n\n",[f(T * 1.8)]).

f(A) -> (round(A*100))/100 . </lang>

Output:
K : 21.0

C : -252.15 

F : -421.87

R : 37.8

ok

Ezhil

<lang Ezhil>

  1. convert from Kelvin

நிரல்பாகம் கெல்வின்_இருந்து_மாற்று( k )

பதிப்பி "Kelvin: ",k,"Celsius: ",round(k-273.15)," Fahrenheit: ",(round(k*1.8 - 459.67))," Rankine: ",(round(k*1.8))

முடி

கெல்வின்_இருந்து_மாற்று( 0 ) #absolute zero கெல்வின்_இருந்து_மாற்று( 273 ) #freezing pt of water கெல்வின்_இருந்து_மாற்று( 30 + 273 ) #room temperature in Summer </lang>

F#

<lang fsharp> // Define units of measure [<Measure>] type k [<Measure>] type f [<Measure>] type c [<Measure>] type r

// Define conversion functions let kelvinToCelsius (t : float<k>) = ((float t) - 273.15) * 1.0<c> let kelvinToFahrenheit (t : float<k>) = (((float t) * 1.8) - 459.67) * 1.0<f> let kelvinToRankine (t : float<k>) = ((float t) * 1.8) * 1.0<r>

// Example code let K = 21.0<k> printfn "%A Kelvin is %A Celsius" K (kelvinToCelsius K) printfn "%A Kelvin is %A Fahrenheit" K (kelvinToFahrenheit K) printfn "%A Kelvin is %A Rankine" K (kelvinToRankine K) </lang>

Go

<lang go>package main

import (

   "fmt"
   "os"
   "strconv"

)

func main() {

   if len(os.Args) != 2 {
       fmt.Println("Usage: k <Kelvin>")
       return
   }
   k, err := strconv.ParseFloat(os.Args[1], 64)
   if err != nil {
       fmt.Println(err)
       return
   }
   if k < 0 {
       fmt.Println("Kelvin must be >= 0.")
       return
   }
   fmt.Printf("K  %.2f\n", k)
   fmt.Printf("C  %.2f\n", k-273.15)
   fmt.Printf("F  %.2f\n", k*9/5-459.67)
   fmt.Printf("R  %.2f\n", k*9/5)

}</lang>

Output:
> k 21
K  21.00
C  -252.15
F  -421.87
R  37.80

Haskell

<lang haskell> main = do

 putStrLn "Please enter temperature in kelvin: "
 input <- getLine
 let kelvin = read input :: Double
 if
   kelvin < 0.0
 then
   putStrLn "error"
 else
   let
     celsius = kelvin - 273.15
     fahrenheit = kelvin * 1.8 - 459.67
     rankine = kelvin * 1.8
   in do
     putStrLn ("kelvin: " ++ show kelvin)
     putStrLn ("celsius: " ++ show celsius)
     putStrLn ("fahrenheit: " ++ show fahrenheit)
     putStrLn ("rankine: " ++ show rankine)

</lang>

Icon and Unicon

The following program works in both languages: <lang unicon>procedure main(A)

   k := A[1] | 21.00
   write("K ",k)
   write("C ",k-273.15)
   write("R ",r := k*(9.0/5.0))
   write("F ",r - 459.67)

end</lang>

Sample runs:

->tc
K 21.0
C -252.15
R 37.8
F -421.87
->tc 273.15
K 273.15
C 0.0
R 491.67
F 32.0
->

J

Solution:<lang j> NB. Temp conversions are all linear polynomials

  K2K    =:     0    1    NB. K = (1  *k) +   0
  K2C    =:  _273    1    NB. C = (1  *k) - 273
  K2F    =:  _459.67 1.8  NB. F = (1.8*k) - 459.67
  K2R    =:     0    1.8  NB. R = (1.8*k) +   0
  NB.  Do all conversions at once (eval 
  NB.  polynomials in parallel). This is the
  NB.  numeric matrix J programs would manipulate
  NB.  directly.
  k2KCFR =:  (K2K , K2C , K2F ,: K2R) p./ ]</lang>
Example:

<lang j> NB. Format matrix for printing

  fmt    =:  '0.2' 8!:0 k2KCFR
  NB.  Tag each temp with scale, for human
  NB.  legibility.
  kcfr   =:  0 _1 |: 'KCFR' ,"0 1"_1 >@:fmt
  
  kcfr 21

K 21.00 C-252.00 F-421.87 R 37.80

  kcfr 0 NB. Absolute zero

K 0.00 C-273.00 F-459.67 R 0.00

  kcfr 21 100 300  NB. List of temps works fine

K 21.00 C-252.00 F-421.87 R 37.80

K 100.00 C-173.00 F-279.67 R 180.00

K 300.00 C 27.00 F 80.33 R 540.00</lang> Notes: The approach is founded on polynomials, one for each conversion (e.g. Fahrenheit = 1.8*x - 459.67 where x is measured in degrees Kelvin), and all polynomials are evaluated simultaneously using the built-in p.. Through some code decorations (specifically the / in p./ the "0 1"_1 and the 0 _1 |:), we permit our function to convert arrays of temperatures of arbitrarily high dimension (a single temp, lists of temps, tables of temps, cubes of temps, etc).

Java

<lang java>public class TemperatureConversion {

   public static void main(String args[]) {
       if (args.length == 1) {
           try {
               double kelvin = Double.parseDouble(args[0]);
               if (kelvin >= 0) {
                   System.out.printf("K  %2.2f\n", kelvin);
                   System.out.printf("C  %2.2f\n", kelvinToCelsius(kelvin));
                   System.out.printf("F  %2.2f\n", kelvinToFahrenheit(kelvin));
                   System.out.printf("R  %2.2f\n", kelvinToRankine(kelvin));
               } else {
                   System.out.printf("%2.2f K is below absolute zero", kelvin);
               }
           } catch (NumberFormatException e) {
               System.out.println(e);
           }
       }
   }
   public static double kelvinToCelsius(double k) {
       return k + 273.15;
   }
   public static double kelvinToFahrenheit(double k) {
       return k * 1.8 - 459.67;
   }
   public static double kelvinToRankine(double k) {
       return k * 1.8;
   }

}</lang>

Output:
K  21.00

C  -252.15

F  -421.87

R  37.80

jq

The hard part here is defining round/1 generically.<lang jq>

  1. round(keep) takes as input any jq (i.e. JSON) number and emits a string.
  2. "keep" is the desired maximum number of numerals after the decimal point,
  3. e.g. 9.999|round(2) => 10.00

def round(keep):

 tostring
 | (index("e") | if . then . else index("E") end) as $e
 | if $e then (.[0:$e] | round(keep)) + .[$e+1:]
   else index(".") as $ix
     | if $ix == null then .
       else .[0:$ix + 1] as $head
         | .[$ix+1:$ix+keep+2] as $tail
         | if ($tail|length) <= keep then $head + $tail
           else ($tail | .[length-1:] | tonumber) as $last
             | if $last < 5 then  $head + $tail[0:$tail|length - 1]
               else (($head + $tail) | length) as $length
                 | ($head[0:-1] + $tail)
                 | (tonumber +  (if $head[0:1]=="-" then -5 else 5 end))
                 | tostring 
                 | .[0: ($ix+1+length-$length)] + "." + .[length-keep-1:-1]
               end
           end
       end
   end;

def k2c: . - 273.15; def k2f: . * 1.8 - 459.67; def k2r: . * 1.8;

  1. produce a stream

def cfr:

 if . >= 0
 then "Kelvin: \(.)", "Celsius: \(k2c|round(2))",
      "Fahrenheit: \(k2f|round(2))", "Rankine: \(k2r|round(2))"
 else error("cfr: \(.) is an invalid temperature in degrees Kelvin")
 end;

cfr</lang> Example <lang sh> $ jq -M -r -f Temperature_conversion.jq

 21
 Kelvin: 21
 Celsius: -252.15
 Fahrenheit: -421.87
 Rankine: 37.80
 
 -1
 jq: error: cfr: -1 is an invalid temperature in degrees Kelvin</lang>

Julia

<lang julia>cfr(k) = print("Kelvin: $k, ",

 "Celsius: $(round(k-273.15,2)), ",
 "Fahrenheit: $(round(k*1.8-459.67,2)), ",
 "Rankine: $(round(k*1.8,2))")</lang>
julia> cfr(21)
Kelvin: 21, Celsius: -252.15, Fahrenheit: -421.87, Rankine: 37.8

Lasso

<lang Lasso>define tempconverter(temp, kind) => {

local( _temp = decimal(#temp), convertratio = 1.8, k_c = 273.15, r_f = 459.67, k,c,r,f )

match(#kind) => { case('k') #k = #_temp #c = -#k_c + #k #r = #k * #convertratio #f = -#r_f + #r case('c') #c = #_temp #k = #k_c + #c #r = #k * #convertratio #f = -#r_f + #r case('r') #r = #_temp #f = -#r_f + #r #k = #r / #convertratio #c = -#k_c + #k case('f') #f = #_temp #r = #r_f + #f #k = #r / #convertratio #c = -#k_c + #k case return 'Something wrong' }

return ('K = ' + #k -> asstring(-precision = 2) + ' C = ' + #c -> asstring(-precision = 2) + ' R = ' + #r -> asstring(-precision = 2) + ' F = ' + #f -> asstring(-precision = 2) ) }

tempconverter(21, 'k') '
' tempconverter(21, 'c') '
' tempconverter(-41, 'c') '
' tempconverter(37.80, 'r') '
' tempconverter(69.80, 'f')</lang>

K = 21.00 C = -252.15 R = 37.80 F = -421.87
K = 294.15 C = 21.00 R = 529.47 F = 69.80
K = 232.15 C = -41.00 R = 417.87 F = -41.80
K = 21.00 C = -252.15 R = 37.80 F = -421.87
K = 294.15 C = 21.00 R = 529.47 F = 69.80

Lua

<lang lua>function convert_temp(k)

   local c = k - 273.15
   local r = k * 1.8
   local f = r - 459.67
   return k, c, r, f

end

print(string.format([[ Kelvin: %.2f K Celcius: %.2f °C Rankine: %.2f °R Fahrenheit: %.2f °F ]],convert_temp(21.0)))</lang>

Mathematica

<lang Mathematica>tempConvert[t_] := Grid[Transpose@{{"K", "C", "F", "R"}, Round[{t, t - 273.15, 9 t/5 - 459.67, 9 t/5}, .01]}]

tempConvert[21]</lang>

Output:

K 21. C -252.15 F -421.87 R 37.8

МК-61/52

<lang mk61>П7 0 , 8 * П8 ИП7 9 * 5 / 3 2 + П9 ИП7 2 7 3 , 1 5 + П4 С/П П8 1 , 8 / БП 00 П9 3 2 - 5 * 9 / БП 00 П4 2 7 3 , 1 5 - БП 00</lang>

Instruction:

tºC = РX В/О С/П;

tºRa = РX БП 25 С/П;

tºF = РX БП 32 С/П;

tK = РX БП 42 С/П;

Result:

РX = Р4 = tK;

Р7 = tºC;

Р8 = tºRa;

Р9 = tºF.

NetRexx

<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols

numeric digits 20

runSample(arg) return

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /*

 +  Kelvin               Celsius        Fahrenheit      Rankine             Delisle        Newton            Réaumur        Rømer
 K  T                    T-273.15       T*9/5-459.67    T*9/5               (373.15-T)*3/2 (T-273.15)*33/100 (T-273.15)*4/5 (T-273.15)*21/40+7.5
 C  T+273.15             T              T*9/5+32        (T+273.15)*9/5      (100-T)*3/2    T*33/100          T*4/5          T*21/40+7.5
 F  (T+459.67)*5/9       (T-32)*5/9     T               T+459.67            (212-T)*5/6    (T-32)*11/60      (T-32)*4/9     (T-32)*7/24+7.5
 R  T*5/9                (T-491.67)*5/9 T-459.67        T                   (671.67-T)*5/6 (T-491.67)*11/60  (T-491.67)*4/9 (T-491.67)*7/24+7.5
 De 373.15-T*2/3         100-T*2/3      212-T*6/5       671.67-T*6/5        T              33-T*11/50        80-T*8/15      60-T*7/20
 N  T*100/33+273.15      T*100/33       T*60/11+32      T*60/11+491.67      (33-T)*50/11   T                 T*80/33        T*35/22+7.5
 Ré T*5/4+273.15         T*5/4          T*9/4+32        T*9/4+491.67        (80-T)*15/8    T*33/80           T              T*21/32+7.5
 Rø (T-7.5)*40/21+273.15 (T-7.5)*40/21  (T-7.5)*24/7+32 (T-7.5)*24/7+491.67 (60-T)*20/7    (T-7.5)*22/35     (T-7.5)*32/21  T
*/

method temperatureConversion(scaleFrom, scaleTo, T) public static

 parse 'KELVIN CELSIUS FAHRENHEIT RANKINE DELISLE NEWTON REAUMUR ROEMER' -
        KELVIN CELSIUS FAHRENHEIT RANKINE DELISLE NEWTON REAUMUR ROEMER .
 scaleFrom = scaleFrom.upper()
 scaleTo   = scaleTo.upper()
 select label sF case scaleFrom
   when KELVIN then do
     select case scaleTo
       when KELVIN     then val = T
       when CELSIUS    then val = T - 273.15
       when FAHRENHEIT then val = T * 9 / 5 - 459.67
       when RANKINE    then val = T * 9 / 5
       when DELISLE    then val = (373.15 - T) * 3 / 2
       when NEWTON     then val = (T - 273.15) * 33 / 100
       when REAUMUR    then val = (T - 273.15) * 4 / 5
       when ROEMER     then val = (T - 273.15) * 21 / 40 + 7.5
       otherwise       signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
       end
     end
   when CELSIUS then do
     select case scaleTo
       when KELVIN     then val = T + 273.15
       when CELSIUS    then val = T
       when FAHRENHEIT then val = T * 9 / 5 + 32
       when RANKINE    then val = (T + 273.15) * 9 / 5
       when DELISLE    then val = (100 - T) * 3 / 2
       when NEWTON     then val = T * 33 / 100
       when REAUMUR    then val = T * 4 / 5
       when ROEMER     then val = T * 21 / 40 + 7.5
       otherwise       signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
       end
     end
   when FAHRENHEIT then do
     select case scaleTo
       when KELVIN     then val = (T + 459.67) * 5 / 9
       when CELSIUS    then val = (T - 32) * 5 / 9
       when FAHRENHEIT then val = T
       when RANKINE    then val = T + 459.67
       when DELISLE    then val = (212 - T) * 5 / 6
       when NEWTON     then val = (T - 32) * 11 / 60
       when REAUMUR    then val = (T - 32) * 4 / 9
       when ROEMER     then val = (T - 32) * 7 / 24 + 7.5
       otherwise       signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
       end
     end
   when RANKINE then do
     select case scaleTo
       when KELVIN     then val = T * 5 / 9
       when CELSIUS    then val = (T - 491.67) * 5 / 9
       when FAHRENHEIT then val = T - 459.67
       when RANKINE    then val = T
       when DELISLE    then val = (671.67 - T) * 5 / 6
       when NEWTON     then val = (T - 491.67) * 11 / 60
       when REAUMUR    then val = (T - 491.67) * 4 / 9
       when ROEMER     then val = (T - 491.67) * 7 / 24 + 7.5
       otherwise       signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
       end
     end
   when DELISLE then do
     select case scaleTo
       when KELVIN     then val = 373.15 - T * 2 / 3
       when CELSIUS    then val = 100 - T * 2 / 3
       when FAHRENHEIT then val = 212 - T * 6 / 5
       when RANKINE    then val = 671.67 - T * 6 / 5
       when DELISLE    then val = T
       when NEWTON     then val = 33 - T * 11 / 50
       when REAUMUR    then val = 80 - T * 8 / 15
       when ROEMER     then val = 60 - T * 7 / 20
       otherwise       signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
       end
     end
   when NEWTON then do
     select case scaleTo
       when KELVIN     then val = T * 100 / 33 + 273.15
       when CELSIUS    then val = T * 100 / 33
       when FAHRENHEIT then val = T * 60 / 11 + 32
       when RANKINE    then val = T * 60 / 11 + 491.67
       when DELISLE    then val = (33 - T) * 50 / 11
       when NEWTON     then val = T
       when REAUMUR    then val = T * 80 / 33
       when ROEMER     then val = T * 35 / 22 + 7.5
       otherwise       signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
       end
     end
   when REAUMUR then do
     select case scaleTo
       when KELVIN     then val = T * 5 / 4 + 273.15
       when CELSIUS    then val = T * 5 / 4
       when FAHRENHEIT then val = T * 9 / 4 + 32
       when RANKINE    then val = T * 9 / 4 + 491.67
       when DELISLE    then val = (80 - T) * 15 / 8
       when NEWTON     then val = T * 33 / 80
       when REAUMUR    then val = T
       when ROEMER     then val = T * 21 / 32 + 7.5
       otherwise       signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
       end
     end
   when ROEMER then do
     select case scaleTo
       when KELVIN     then val = (T - 7.5) * 40 / 21 + 273.15
       when CELSIUS    then val = (T - 7.5) * 40 / 21
       when FAHRENHEIT then val = (T - 7.5) * 24 / 7 + 32
       when RANKINE    then val = (T - 7.5) * 24 / 7 + 491.67
       when DELISLE    then val = (60 - T) * 20 / 7
       when NEWTON     then val = (T - 7.5) * 22 / 35
       when REAUMUR    then val = (T - 7.5) * 32 / 21
       when ROEMER     then val = T
       otherwise       signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
       end
     end
   otherwise
     signal IllegalArgumentException(scaleFrom',' scaleTo',' T)
   end sF
 return val

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method runSample(arg) public static

 tlist = [ -
 /* C....... F....... K....... R.......*/ -
   ' 5500.00  9932.00  5773.15 10391.67', -
   '  300.00   572.00   573.15  1031.67', -
   '  200.00   392.00   473.15   851.67', -
   '  100.00   212.00   373.15   671.67', -
   '   37.00    98.60   310.15   558.27', -
   '    0.00    32.00   273.15   491.67', -
   ' -100.00  -148.00   173.15   311.67', -
   ' -200.00  -328.00    73.15   131.67', -
   ' -252.15  -421.87    21.00    37.80', -
   ' -273.15  -459.67     0.00     0.00'  -
   ]
 parse 'CELSIUS FAHRENHEIT KELVIN RANKINE' CELSIUS FAHRENHEIT KELVIN RANKINE .
 loop temp over tlist
   parse temp ttC ttF ttK ttR .
   say '   C....... F....... K....... R.......'
   say 'C ' -
       temperatureConversion(CELSIUS,    CELSIUS,    ttC).format(5, 2) -
       temperatureConversion(CELSIUS,    FAHRENHEIT, ttC).format(5, 2) -
       temperatureConversion(CELSIUS,    KELVIN,     ttC).format(5, 2) -
       temperatureConversion(CELSIUS,    RANKINE,    ttC).format(5, 2)
 
   say 'F ' -
       temperatureConversion(FAHRENHEIT, CELSIUS,    ttF).format(5, 2) -
       temperatureConversion(FAHRENHEIT, FAHRENHEIT, ttF).format(5, 2) -
       temperatureConversion(FAHRENHEIT, KELVIN,     ttF).format(5, 2) -
       temperatureConversion(FAHRENHEIT, RANKINE,    ttF).format(5, 2)
 
   say 'K ' -
       temperatureConversion(KELVIN,     CELSIUS,    ttK).format(5, 2) -
       temperatureConversion(KELVIN,     FAHRENHEIT, ttK).format(5, 2) -
       temperatureConversion(KELVIN,     KELVIN,     ttK).format(5, 2) -
       temperatureConversion(KELVIN,     RANKINE,    ttK).format(5, 2)
 
   say 'R ' -
       temperatureConversion(RANKINE,    CELSIUS,    ttR).format(5, 2) -
       temperatureConversion(RANKINE,    FAHRENHEIT, ttR).format(5, 2) -
       temperatureConversion(RANKINE,    KELVIN,     ttR).format(5, 2) -
       temperatureConversion(RANKINE,    RANKINE,    ttR).format(5, 2)
   say
   end temp
 return

</lang>

Output:
   C....... F....... K....... R.......
C   5500.00  9932.00  5773.15 10391.67
F   5500.00  9932.00  5773.15 10391.67
K   5500.00  9932.00  5773.15 10391.67
R   5500.00  9932.00  5773.15 10391.67

   C....... F....... K....... R.......
C    300.00   572.00   573.15  1031.67
F    300.00   572.00   573.15  1031.67
K    300.00   572.00   573.15  1031.67
R    300.00   572.00   573.15  1031.67

   C....... F....... K....... R.......
C    200.00   392.00   473.15   851.67
F    200.00   392.00   473.15   851.67
K    200.00   392.00   473.15   851.67
R    200.00   392.00   473.15   851.67

   C....... F....... K....... R.......
C    100.00   212.00   373.15   671.67
F    100.00   212.00   373.15   671.67
K    100.00   212.00   373.15   671.67
R    100.00   212.00   373.15   671.67

   C....... F....... K....... R.......
C     37.00    98.60   310.15   558.27
F     37.00    98.60   310.15   558.27
K     37.00    98.60   310.15   558.27
R     37.00    98.60   310.15   558.27

   C....... F....... K....... R.......
C      0.00    32.00   273.15   491.67
F      0.00    32.00   273.15   491.67
K      0.00    32.00   273.15   491.67
R      0.00    32.00   273.15   491.67

   C....... F....... K....... R.......
C   -100.00  -148.00   173.15   311.67
F   -100.00  -148.00   173.15   311.67
K   -100.00  -148.00   173.15   311.67
R   -100.00  -148.00   173.15   311.67

   C....... F....... K....... R.......
C   -200.00  -328.00    73.15   131.67
F   -200.00  -328.00    73.15   131.67
K   -200.00  -328.00    73.15   131.67
R   -200.00  -328.00    73.15   131.67

   C....... F....... K....... R.......
C   -252.15  -421.87    21.00    37.80
F   -252.15  -421.87    21.00    37.80
K   -252.15  -421.87    21.00    37.80
R   -252.15  -421.87    21.00    37.80

   C....... F....... K....... R.......
C   -273.15  -459.67     0.00     0.00
F   -273.15  -459.67     0.00     0.00
K   -273.15  -459.67     0.00     0.00
R   -273.15  -459.67     0.00     0.00

Nimrod

<lang nimrod>import rdstdin, strutils, strfmt

while true:

 let k = parseFloat readLineFromStdin "K ? "
 echo "{:g} Kelvin = {:g} Celsius = {:g} Fahrenheit = {:g} Rankine degrees".fmt(
   k, k - 273.15, k * 1.8 - 459.67, k * 1.8)</lang>

Sample usage:

K ? 21.0
21 Kelvin = -252.15 Celsius = -421.87 Fahrenheit = 37.8 Rankine degrees
K ? 222.2
222.2 Kelvin = -50.95 Celsius = -59.71 Fahrenheit = 399.96 Rankine degrees

Objeck

<lang objeck> class Temperature {

 function : Main(args : String[]) ~ Nil {
   k := System.IO.Console->ReadString()->ToFloat();
   c := KelvinToCelsius(k);
   f := KelvinToFahrenheit(k);
   r := KelvinToRankine(k);
   "K: {$k}"->PrintLine();
   "C: {$c}"->PrintLine();
   "F: {$f}"->PrintLine();
   "R: {$r}"->PrintLine();
 }
 function : KelvinToCelsius(k : Float) ~ Float {
   return k - 273.15;
 }

 function : KelvinToFahrenheit(k : Float) ~ Float {
   return k * 1.8 - 459.67;
 }

 function : KelvinToRankine(k : Float) ~ Float {
   return k * 1.8;
 }

} </lang>

K: 21.0
C: -252.150
F: -421.870
R: 37.800

Objective-C

<lang objc>#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {

   @autoreleasepool {
       if(argc > 1)
       {
           NSString *arg1 = [NSString stringWithCString:argv[1] encoding:NSUTF8StringEncoding]; 
           // encoding shouldn't matter in this case
           double kelvin = [arg1 doubleValue];
           
           NSLog(@"K %.2f",kelvin);
           NSLog(@"C %.2f\n", kelvin - 273.15);
           NSLog(@"F %.2f\n", (kelvin * 1.8) - 459.67);
           NSLog(@"R %.2f", kelvin * 1.8);
       }
   }
   return 0;

}</lang>

PARI/GP

<lang parigp>f(x)=[x,x-273.15,1.8*x-459.67,1.8*x]</lang>

Perl

<lang Perl>my %scale = (

   Celcius    => { factor => 1  , offset => -273.15 },
   Rankine    => { factor => 1.8, offset =>    0    },
   Fahrenheit => { factor => 1.8, offset => -459.67 },

);

print "Enter a temperature in Kelvin: "; chomp(my $kelvin = <STDIN>); die "No such temperature!\n" unless $kelvin > 0;

foreach (sort keys %scale) {

   printf "%12s:%8.2f\n", $_, $kelvin * $scale{$_}{factor} + $scale{$_}{offset};

}</lang>

Output:
Enter a temperature in Kelvin: 21
     Celcius: -252.15
  Fahrenheit: -421.87
     Rankine:   37.80

Perl 6

<lang perl6>while ne my $answer = prompt 'Temperature: ' {

   my $k = do given $answer {
       when s/:i C $// { $_ + 273.15 }
       when s/:i F $// { ($_ + 459.67) / 1.8 }
       when s/:i R $// { $_ / 1.8 }
       when s/:i K $// { $_ }
       default         { $_ }
   }
   say "  { $k }K";
   say "  { $k - 273.15 }℃";
   say "  { $k * 1.8 - 459.67 }℉";
   say "  { $k * 1.8 }R";

}</lang>

Output:
Temperature: 0
  0K
  -273.15℃
  -459.67℉
  0R
Temperature: 0c
  273.15K
  0℃
  32℉
  491.67R
Temperature: 212f
  373.15K
  100℃
  212℉
  671.67R
Temperature: -40c
  233.15K
  -40℃
  -40℉
  419.67R

PHP

<lang php>error_reporting(E_ALL & ~ ( E_NOTICE | E_WARNING ));

while (true) {

   echo "\nEnter a value in kelvin (q to quit): ";
   if (($kelvin = trim(fgets(STDIN))) !== false) {
       if ($kelvin == 'q') {
           echo 'quitting';
           break;
       }
       if (is_numeric($kelvin)) {
           $kelvin = floatVal($kelvin);
           if ($kelvin >= 0) {
               printf(" K  %2.2f\n", $kelvin);
               printf(" C  %2.2f\n", $kelvin - 273.15);
               printf(" F  %2.2f\n", $kelvin * 1.8 - 459.67);
               printf(" R  %2.2f\n", $kelvin * 1.8);
           } else printf(" %2.2f K is below absolute zero\n", $kelvin);
       }
   }

}</lang>

Output:
Enter a value in kelvin (q to quit): 21
 K  21.00
 C  -252.15
 F  -421.87
 R  37.80

Enter a value in kelvin (q to quit): q
quitting

PicoLisp

<lang PicoLisp>(scl 2)

(de convertKelvin (Kelvin)

  (for X
     (quote
        (K . prog)
        (C (K) (- K 273.15))
        (F (K) (- (*/ K 1.8 1.0) 459.67))
        (R (K) (*/ K 1.8 1.0)) )
     (tab (-3 8)
        (car X)
        (format ((cdr X) Kelvin) *Scl) ) ) )</lang>

Test: <lang PicoLisp>(convertKelvin 21.0)</lang>

Output:
K     21.00
C   -252.15
F   -421.87
R     37.80

PL/I

<lang pli>*process source attributes xref;

/* PL/I **************************************************************
* 15.08.2013 Walter Pachl translated from NetRexx
* temperatures below 0K are considered invalid
*********************************************************************/
temperature: Proc Options(main);
Dcl sysin record Input;
On Endfile(sysin) Goto eoj;
On Record(sysin);
Dcl 1 dat,
     2 t Pic'SSSS9V.99',
     2 *    char( 1),
     2 from char(10),
     2 *    char( 1),
     2 to   char(10);
Do Forever;
  Read File(sysin) Into(dat);
  If tc(t,from,'KELVIN')<0 Then
    Put Edit('Input (',t,from,') invalid. Below absolute zero')
            (Skip,a,f(8,2),x(1),a,a);
  Else
    Put edit(t,from,' -> ',tc(t,from,to),to)
            (skip,f(8,2),x(1),a(10),a,f(8,2),x(1),a(10));
  End;
eoj: Return;
tc: Procedure(T,scaleFrom,scaleTo) Returns(Dec Fixed(8,2));
Dcl t Pic'SSSS9V.99';
Dcl (val) Dec Fixed(8,2);
Dcl (scaleFrom,scaleTo) Char(10);
 select(scaleFrom);
   when('KELVIN ') do;
     select(scaleTo);
       when('KELVIN    ') val = T;
       when('CELSIUS   ') val = T - 273.15;
       when('FAHRENHEIT') val = T * 9 / 5 - 459.67;
       when('RANKINE   ') val = T * 9 / 5;
       when('DELISLE   ') val = (373.15 - T) * 3 / 2;
       when('NEWTON    ') val = (T - 273.15) * 33 / 100;
       when('REAUMUR   ') val = (T - 273.15) * 4 / 5;
       when('ROEMER    ') val = (T - 273.15) * 21 / 40 + 7.5;
       otherwise Do;
         Put Edit('scaleTo=',scaleTo)(Skip,a,a);
         Call err(1);
         End;
       end;
     end;
   when('CELSIUS') do;
     select(scaleTo);
       when('KELVIN    ') val = T + 273.15;
       when('CELSIUS   ') val = T;
       when('FAHRENHEIT') val = T * 9 / 5 + 32;
       when('RANKINE   ') val = (T + 273.15) * 9 / 5;
       when('DELISLE   ') val = (100 - T) * 3 / 2;
       when('NEWTON    ') val = T * 33 / 100;
       when('REAUMUR   ') val = T * 4 / 5;
       when('ROEMER    ') val = T * 21 / 40 + 7.5;
       otherwise Call err(2);
       end;
     end;
   when('FAHRENHEIT') do;
     select(scaleTo);
       when('KELVIN    ') val = (T + 459.67) * 5 / 9;
       when('CELSIUS   ') val = (T - 32) * 5 / 9;
       when('FAHRENHEIT') val = T;
       when('RANKINE   ') val = T + 459.67;
       when('DELISLE   ') val = (212 - T) * 5 / 6;
       when('NEWTON    ') val = (T - 32) * 11 / 60;
       when('REAUMUR   ') val = (T - 32) * 4 / 9;
       when('ROEMER    ') val = (T - 32) * 7 / 24 + 7.5;
       otherwise Call err(3);
       end;
     end;
   when('RANKINE') do;
     select(scaleTo);
       when('KELVIN    ') val = T * 5 / 9;
       when('CELSIUS   ') val = (T - 491.67) * 5 / 9;
       when('FAHRENHEIT') val = T - 459.67;
       when('RANKINE   ') val = T;
       when('DELISLE   ') val = (671.67 - T) * 5 / 6;
       when('NEWTON    ') val = (T - 491.67) * 11 / 60;
       when('REAUMUR   ') val = (T - 491.67) * 4 / 9;
       when('ROEMER    ') val = (T - 491.67) * 7 / 24 + 7.5;
       otherwise Call err(4);
       end;
     end;
   when('DELISLE') do;
     select(scaleTo);
       when('KELVIN    ') val = 373.15 - T * 2 / 3;
       when('CELSIUS   ') val = 100 - T * 2 / 3;
       when('FAHRENHEIT') val = 212 - T * 6 / 5;
       when('RANKINE   ') val = 671.67 - T * 6 / 5;
       when('DELISLE   ') val = T;
       when('NEWTON    ') val = 33 - T * 11 / 50;
       when('REAUMUR   ') val = 80 - T * 8 / 15;
       when('ROEMER    ') val = 60 - T * 7 / 20;
       otherwise Call err(5);
       end;
     end;
   when('NEWTON') do;
     select(scaleTo);
       when('KELVIN    ') val = T * 100 / 33 + 273.15;
       when('CELSIUS   ') val = T * 100 / 33;
       when('FAHRENHEIT') val = T * 60 / 11 + 32;
       when('RANKINE   ') val = T * 60 / 11 + 491.67;
       when('DELISLE   ') val = (33 - T) * 50 / 11;
       when('NEWTON    ') val = T;
       when('REAUMUR   ') val = T * 80 / 33;
       when('ROEMER    ') val = T * 35 / 22 + 7.5;
       otherwise Call err(6);
       end;
     end;
   when('REAUMUR') do;
     select(scaleTo);
       when('KELVIN    ') val = T * 5 / 4 + 273.15;
       when('CELSIUS   ') val = T * 5 / 4;
       when('FAHRENHEIT') val = T * 9 / 4 + 32;
       when('RANKINE   ') val = T * 9 / 4 + 491.67;
       when('DELISLE   ') val = (80 - T) * 15 / 8;
       when('NEWTON    ') val = T * 33 / 80;
       when('REAUMUR   ') val = T;
       when('ROEMER    ') val = T * 21 / 32 + 7.5;
       otherwise Call err(7);
       end;
     end;
   when('ROEMER') do;
     select(scaleTo);
       when('KELVIN    ') val = (T - 7.5) * 40 / 21 + 273.15;
       when('CELSIUS   ') val = (T - 7.5) * 40 / 21;
       when('FAHRENHEIT') val = (T - 7.5) * 24 / 7 + 32;
       when('RANKINE   ') val = (T - 7.5) * 24 / 7 + 491.67;
       when('DELISLE   ') val = (60 - T) * 20 / 7;
       when('NEWTON    ') val = (T - 7.5) * 22 / 35;
       when('REAUMUR   ') val = (T - 7.5) * 32 / 21;
       when('ROEMER    ') val = T;
       otherwise Call err(8);
       end;
     end;
   otherwise Call err(9);
   end;
 return(val);
 err: Proc(e);
 Dcl e Dec fixed(1);
 Put Edit('error ',e,' invalid input')(Skip,a,f(1),a);
 val=0;
 End;
 End;
End;</lang>
Output:
   21.00 KELVIN     ->  -252.15 CELSIUS
   21.00 KELVIN     ->  -421.87 FAHRENHEIT
   21.00 KELVIN     ->    37.80 RANKINE
Input (  600.00 DELISLE   ) invalid. Below absolute zero
Input (   -1.00 KELVIN    ) invalid. Below absolute zero
Input ( -300.00 CELSIUS   ) invalid. Below absolute zero
  212.00 FAHRENHEIT ->   100.00 CELSIUS
    0.00 FAHRENHEIT ->   -17.77 CELSIUS
    0.00 CELSIUS    ->    32.00 FAHRENHEIT
   37.00 CELSIUS    ->    98.60 FAHRENHEIT

Pure Data

temperature.pd

#N canvas 200 200 640 600 10;
#X floatatom 130 54 8 0 0 2 Kelvin chgk -;
#X obj 130 453 rnd2;
#X floatatom 130 493 8 0 0 1 K - -;
#X floatatom 251 54 8 0 0 2 Celsius chgc -;
#X obj 251 453 rnd2;
#X floatatom 251 493 8 0 0 1 °C - -;
#X floatatom 374 54 8 0 0 2 Fahrenheit chgf -;
#X obj 374 453 rnd2;
#X floatatom 374 493 8 0 0 1 °F - -;
#X floatatom 498 54 8 0 0 2 Rankine chgr -;
#X obj 498 453 rnd2;
#X floatatom 498 493 8 0 0 1 °Ra - -;
#X obj 65 133 - 273.15;
#X obj 65 244 * 1.8;
#X obj 65 267 + 32;
#X obj 65 363 + 459.67;
#X obj 186 133 * 1.8;
#X obj 186 156 + 32;
#X obj 186 268 + 459.67;
#X obj 186 310 / 1.8;
#X obj 309 133 + 459.67;
#X obj 309 215 / 1.8;
#X obj 309 291 - 273.15;
#X obj 433 133 / 1.8;
#X obj 433 223 - 273.15;
#X obj 433 294 * 1.8;
#X obj 433 317 + 32;
#X text 20 53 Input:;
#X text 20 492 Output:;
#X connect 0 0 1 0;
#X connect 0 0 12 0;
#X connect 1 0 2 0;
#X connect 3 0 4 0;
#X connect 3 0 16 0;
#X connect 4 0 5 0;
#X connect 6 0 7 0;
#X connect 6 0 20 0;
#X connect 7 0 8 0;
#X connect 9 0 10 0;
#X connect 9 0 23 0;
#X connect 10 0 11 0;
#X connect 12 0 13 0;
#X connect 12 0 4 0;
#X connect 13 0 14 0;
#X connect 14 0 15 0;
#X connect 14 0 7 0;
#X connect 15 0 10 0;
#X connect 16 0 17 0;
#X connect 17 0 18 0;
#X connect 17 0 7 0;
#X connect 18 0 19 0;
#X connect 18 0 10 0;
#X connect 19 0 1 0;
#X connect 20 0 21 0;
#X connect 20 0 10 0;
#X connect 21 0 22 0;
#X connect 21 0 1 0;
#X connect 22 0 4 0;
#X connect 23 0 24 0;
#X connect 23 0 1 0;
#X connect 24 0 25 0;
#X connect 24 0 4 0;
#X connect 25 0 26 0;
#X connect 26 0 7 0;

Plugin to round the results to at most 2 digits:

rnd.pd

#N canvas 880 200 450 300 10;
#X obj 77 34 inlet;
#X obj 77 113 * 100;
#X obj 77 135 + 0.5;
#X obj 132 135 < 0;
#X obj 77 172 -;
#X obj 77 194 int;
#X obj 77 216 / 100;
#X obj 77 238 outlet;
#X connect 0 0 1 0;
#X connect 0 0 3 0;
#X connect 1 0 2 0;
#X connect 2 0 4 0;
#X connect 3 0 4 1;
#X connect 4 0 5 0;
#X connect 5 0 6 0;
#X connect 6 0 7 0;

Python

<lang python>>>> while True: k = float(input('K ? ')) print("%g Kelvin = %g Celsius = %g Fahrenheit = %g Rankine degrees."  % (k, k - 273.15, k * 1.8 - 459.67, k * 1.8))


K ? 21.0 21 Kelvin = -252.15 Celsius = -421.87 Fahrenheit = 37.8 Rankine degrees. K ? 222.2 222.2 Kelvin = -50.95 Celsius = -59.71 Fahrenheit = 399.96 Rankine degrees. K ? </lang>

Python: Universal conversion

This converts from any one of the units to all the others <lang python>>>> toK = {'C': (lambda c: c + 273.15),

          'F': (lambda f: (f + 459.67) / 1.8),
          'R': (lambda r: r / 1.8),
          'K': (lambda k: k) }

>>> while True: magnitude, unit = input('<value> <K/R/F/C> ? ').split() k = toK[unit](float(magnitude)) print("%g Kelvin = %g Celsius = %g Fahrenheit = %g Rankine degrees."  % (k, k - 273.15, k * 1.8 - 459.67, k * 1.8))


<value> <K/R/F/C> ? 222.2 K 222.2 Kelvin = -50.95 Celsius = -59.71 Fahrenheit = 399.96 Rankine degrees. <value> <K/R/F/C> ? -50.95 C 222.2 Kelvin = -50.95 Celsius = -59.71 Fahrenheit = 399.96 Rankine degrees. <value> <K/R/F/C> ? -59.71 F 222.2 Kelvin = -50.95 Celsius = -59.71 Fahrenheit = 399.96 Rankine degrees. <value> <K/R/F/C> ? 399.96 R 222.2 Kelvin = -50.95 Celsius = -59.71 Fahrenheit = 399.96 Rankine degrees. <value> <K/R/F/C> ? </lang>

Racket

Althoguh not exactly the shortest code, the converter function can turn any temperature into any other <lang Racket>#lang racket (define (converter temp init final)

 (define to-k
   (case init
     ('k temp)
     ('c (+ 273.15 temp))
     ('f (* (+ temp 459.67) 5/9))
     ('r (* temp 5/9))))
 (case final
   ('k to-k)
   ('c (- to-k 273.15))
   ('f (- (* to-k 9/5) 459.67))
   ('r (* to-k 1.8))))

(define (kelvin-to-all temp)

 (display (format "Kelvin: ~a \nCelsius: ~a \nFahrenheit: ~a \nRankine: ~a \n"
                  temp
                  (converter temp 'k 'c)
                  (converter temp 'k 'f)
                  (converter temp 'k 'r))))

(kelvin-to-all 21)

Kelvin
21
Celsius
-252.14999999999998
Fahrenheit
-421.87
Rankine
37.800000000000004

</lang>

REXX

This REXX version supports:

  • (alternate spellings with optional   degree   or   degrees   preceding the scale name):
    • centigrade, centingrade, centesimal, Celsius, and some misspellings
    • Delisle
    • Fahrenheit, and some misspellings
    • Kelvin, and some misspellings
    • Newton, and a misspelling
    • Rankine
    • Reaumur, Réaumur
    • Romer   (Rømer),   Roemer
  • multiple temperatures in a list
  • specification of which temperature to be used for conversion
  • conversion of a temperature to all eight temperatures
  • comments within the list
  • aligned output (whole numbers and decimal fractions)

<lang rexx>/*REXX program converts temperature for: C, D, F, N, Ra, Re, Ro, and K.*/ parse arg tList /*get specified temperature lists*/

 do  until  tList=                  /*process a list of temperatures.*/
 parse  var tList  x  ','  tList      /*temps are separated by commas. */
 x=translate(x,'((',"[{")             /*support other grouping symbols.*/
 x=space(x);  parse var x z '('       /*handle any comments (if any).  */
 if z==     then call serr 'no arguments were specified.'
 _=verify(z, '+-.0123456789')         /*a list of valid number thingys.*/
 n=z
 if _\==0  then do
                if _==1  then call serr 'illegal temperature:'  z
                n=left(z, _-1)        /*pick off the number (hopefully)*/
                u=strip(substr(z, _)) /*pick off the temperature unit. */
                end
           else u='k'                 /*assume  Kelvin as per task req.*/
 uU=translate(u,'eE',"éÉ");  upper uU /*uppercase version of temp unit.*/
 if left(uU,7)=='DEGREES' then uU=substr(uU,8)  /*redundant "degrees"? */
 if left(uU,6)=='DEGREE'  then uU=substr(uU,7)  /*   "      "degree" ? */
 uU=strip(uU)
 if \datatype(n,'N')  then call serr 'illegal number:' n
                                      /*accept alternate spellings.    */
     select                           /*convert ──►  ºF  temperatures. */
     when abbrev('CENTIGRADE' , uU)    |,
          abbrev('CENTRIGRADE', uU)    |,            /* 50% misspelled.*/
          abbrev('CETIGRADE'  , uU)    |,            /* 50% misspelled.*/
          abbrev('CENTINGRADE', uU)    |,
          abbrev('CENTESIMAL' , uU)    |,
          abbrev('CELCIUS'    , uU)    |,            /* 82% misspelled.*/
          abbrev('CELCIOUS'   , uU)    |,            /*  4% misspelled.*/
          abbrev('CELCUIS'    , uU)    |,            /*  4% misspelled.*/
          abbrev('CELSUIS'    , uU)    |,            /*  2% misspelled.*/
          abbrev('CELCEUS'    , uU)    |,            /*  2% misspelled.*/
          abbrev('CELCUS'     , uU)    |,            /*  2% misspelled.*/
          abbrev('CELISUS'    , uU)    |,            /*  1% misspelled.*/
          abbrev('CELSUS'     , uU)    |,            /*  1% misspelled.*/
          abbrev('CELSIUS'    , uU)       then F=n       *  9/5   +  32
     when abbrev('DELISLE'    , uU)       then F=212 -(n *  6/5)
     when abbrev('FARENHEIT'  , uU)    |,            /* 39% misspelled.*/
          abbrev('FARENHEIGHT', uU)    |,            /* 15% misspelled.*/
          abbrev('FARENHITE'  , uU)    |,            /*  6% misspelled.*/
          abbrev('FARENHIET'  , uU)    |,            /*  3% misspelled.*/
          abbrev('FARHENHEIT' , uU)    |,            /*  3% misspelled.*/
          abbrev('FARINHEIGHT', uU)    |,            /*  2% misspelled.*/
          abbrev('FARENHIGHT' , uU)    |,            /*  2% misspelled.*/
          abbrev('FAHRENHIET' , uU)    |,            /*  2% misspelled.*/
          abbrev('FERENHEIGHT', uU)    |,            /*  2% misspelled.*/
          abbrev('FEHRENHEIT' , uU)    |,            /*  2% misspelled.*/
          abbrev('FERENHEIT'  , uU)    |,            /*  2% misspelled.*/
          abbrev('FERINHEIGHT', uU)    |,            /*  1% misspelled.*/
          abbrev('FARIENHEIT' , uU)    |,            /*  1% misspelled.*/
          abbrev('FARINHEIT'  , uU)    |,            /*  1% misspelled.*/
          abbrev('FARANHITE'  , uU)    |,            /*  1% misspelled.*/
          abbrev('FAHRENHEIT' , uU)      then F=n
     when abbrev('KELVINS'    , uU)    |,            /* 46% misspelled.*/
          abbrev('KALVIN'     , uU)    |,            /* 27% misspelled.*/
          abbrev('KERLIN'     , uU)    |,            /* 18% misspelled.*/
          abbrev('KEVEN'      , uU)    |,            /*  9% misspelled.*/
          abbrev('KELVIN'     , uU)      then F=n       *  9/5   - 459.67
     when abbrev('NEUTON'     , uU)    |,            /*100% misspelled.*/
          abbrev('NEWTON'     , uU)      then F=n       * 60/11  +  32
                                    /*a single  R  is taken as Rankine.*/
     when abbrev('RANKINE'    , uU)      then F=n                - 459.67
     when abbrev('REAUMUR'    , uU, 2)   then F=n       *  9/4   +  32
     when abbrev('ROEMER'     , uU, 2) |,
          abbrev('ROMER'      , uU, 2)   then F=(n-7.5) * 27/4   +  32
     otherwise           call serr  'illegal temperature scale:'  u
     end   /*select*/
 say right(' ' x,55,"─")              /*show original value&scale, sep.*/
 say Tform( ( F   - 32     )   *  5/9           )    'Celsius'
 say Tform( ( 212 - F      )   *  5/6           )    'Delisle'
 say Tform(   F                                 )    'Fahrenheit'
 say Tform( ( F   + 459.67 )   *  5/9           )    'Kelvin'
 say Tform( ( F   - 32     )   *  11/60         )    'Newton'
 say Tform(   F   + 459.67                      )    'Rankine'
 say Tform( ( F   - 32     )   *  4/9           )    'Reaumur'
 say Tform( ( F   - 32     )   *  7/24    + 7.5 )    'Romer'
 end   /*until tlist= */

exit /*stick a fork in it, we're done.*/ /*──────────────────────────────────TFORM subroutine────────────────────*/ Tform: procedure; showDig=8 /*only show 8 significant digits.*/ _=format(arg(1),,showDig)/1 /*format arg 8 digs past the . */ p=pos('.',_) /*find position of decimal point.*/

                                      /* [↓] align integers with FP #s.*/

if p==0 then _=_ || left(,showDig+1) /*no decimal point.*/

        else _=_ || left(,showDig-length(_)+p)   /*has    "      "   */

return right(_,20) /*return the re-formatted arg. */ /*──────────────────────────────────SERR subroutine─────────────────────*/ serr: say; say '***error!***'; say; say arg(1); say; exit 13</lang>

Output:

when using the input of

-40C, 0 c (water freezes), 37C (body temp), 100 C (water boils), 21 degrees Kelvin, 0K (outer space?)
─────────────────────────────────────────────────  -40C
        -40          Celsius
        210          Delisle
        -40          Fahrenheit
        233.15       Kelvin
        -13.2        Newton
        419.67       Rankine
        -32          Reaumur
        -13.5        Romer
──────────────────────────────────  0 c (water freezes)
          0          Celsius
        150          Delisle
         32          Fahrenheit
        273.15       Kelvin
          0          Newton
        491.67       Rankine
          0          Reaumur
          7.5        Romer
──────────────────────────────────────  37C (body temp)
         37          Celsius
         94.5        Delisle
         98.6        Fahrenheit
        310.15       Kelvin
         12.21       Newton
        558.27       Rankine
         29.6        Reaumur
         26.925      Romer
──────────────────────────────────  100 C (water boils)
        100          Celsius
          0          Delisle
        212          Fahrenheit
        373.15       Kelvin
         33          Newton
        671.67       Rankine
         80          Reaumur
         60          Romer
────────────────────────────────────  21 degrees Kelvin
       -252.15       Celsius
        528.225      Delisle
       -421.87       Fahrenheit
         21          Kelvin
        -83.2095     Newton
         37.8        Rankine
       -201.72       Reaumur
       -124.87875    Romer
────────────────────────────────────  0K (outer space?)
       -273.15       Celsius
        559.725      Delisle
       -459.67       Fahrenheit
          0          Kelvin
        -90.1395     Newton
          0          Rankine
       -218.52       Reaumur
       -135.90375    Romer

[Actually, water freezes at 0.000089º C,   and boils at 99.974º C.]

Ruby

<lang ruby>module TempConvert

 FROM_TEMP_SCALE_TO_K = 
 {'kelvin'     => lambda{|t| t},
  'celsius'    => lambda{|t| t + 273.15},
  'fahrenheit' => lambda{|t| (t + 459.67) * 5/9.0},
  'rankine'    => lambda{|t| t * 5/9.0},
  'delisle'    => lambda{|t| 373.15 - t * 2/3.0},
  'newton'     => lambda{|t| t * 100/33.0 + 273.15},
  'reaumur'    => lambda{|t| t * 5/4.0 + 273.15},
  'roemer'     => lambda{|t| (t - 7.5) * 40/21.0 + 273.15}}
 TO_TEMP_SCALE_FROM_K = 
 {'kelvin'     => lambda{|t| t},
  'celsius'    => lambda{|t| t - 273.15},
  'fahrenheit' => lambda{|t| t * 9/5.0 - 459.67},
  'rankine'    => lambda{|t| t * 9/5.0},
  'delisle'    => lambda{|t| (373.15 - t) * 3/2.0},
  'newton'     => lambda{|t| (t - 273.15) * 33/100.0},
  'reaumur'    => lambda{|t| (t - 273.15) * 4/5.0},
  'roemer'     => lambda{|t| (t - 273.15) * 21/40.0 + 7.5}}
 
 SUPPORTED_SCALES = FROM_TEMP_SCALE_TO_K.keys.join('|')
 def self.method_missing(meth, *args, &block)
   if valid_temperature_conversion?(meth) then
     convert_temperature(meth, *args)
   else
     super
   end
 end
 def self.respond_to_missing?(meth, include_private = false)
   valid_temperature_conversion?(meth) || super
 end

 def self.valid_temperature_conversion?(meth)
   !!(meth.to_s =~ /(#{SUPPORTED_SCALES})_to_(#{SUPPORTED_SCALES})/) 
 end
 
 def self.convert_temperature(meth, temp)
   from_scale, to_scale = meth.to_s.split("_to_")
   return temp.to_f if from_scale == to_scale # no kelvin roundtrip 
   TO_TEMP_SCALE_FROM_K[to_scale].call(FROM_TEMP_SCALE_TO_K[from_scale].call(temp)).round(2)
 end

end</lang> Converts all eight scales to any other scale, by means of method_missing.

Usage: <lang ruby>TempConvert.kelvin_to_celsius 100 #=> -173.15 TempConvert.kelvin_to_fahrenheit 100 #=> -279.67 TempConvert.kelvin_to_rankine 100 #=> 180.0 TempConvert.kelvin_to_delisle 100 #=> 409.73 TempConvert.kelvin_to_newton 100 #=> -57.14 TempConvert.kelvin_to_reaumur 100 #=> -138.52 TempConvert.kelvin_to_roemer 100 #=> -83.4

TempConvert.newton_to_celsius 100 #=> 303.03 TempConvert.newton_to_fahrenheit 100 #=> 577.45

  1. All 64 combinations possible</lang>

Run BASIC

<lang runbasic>[loop] input "Kelvin Degrees";kelvin if kelvin <= 0 then end ' zero or less ends the program celcius = kelvin - 273.15 fahrenheit = kelvin * 1.8 - 459.67 rankine = kelvin * 1.8 print kelvin;" kelvin is equal to ";celcius; " degrees celcius and ";fahrenheit;" degrees fahrenheit and ";rankine; " degrees rankine" goto [loop]</lang>

Scala

Library: Scala

<lang Scala>object TemperatureConversion extends App {

 def kelvinToCelsius(k: Double) = k + 273.15
 def kelvinToFahrenheit(k: Double) = k * 1.8 - 459.67
 def kelvinToRankine(k: Double) = k * 1.8
 if (args.length == 1) {
   try {
     val kelvin = args(0).toDouble
     if (kelvin >= 0) {
       println(f"K  $kelvin%2.2f")
       println(f"C  ${kelvinToCelsius(kelvin)}%2.2f")
       println(f"F  ${kelvinToFahrenheit(kelvin)}%2.2f")
       println(f"R  ${kelvinToRankine(kelvin)}%2.2f")
     } else println("%2.2f K is below absolute zero", kelvin)
   } catch {
     case e: NumberFormatException => System.out.println(e)
     case e: Throwable => {
       println("Some other exception type:")
       e.printStackTrace()
     }
   }
 } else println("Temperature not given.")

}</lang>

Output:
K  21,00
C  294,15
F  -421,87
R  37,80

Seed7

<lang seed7>$ include "seed7_05.s7i";

 include "float.s7i";

const func float: celsius (in float: kelvin) is

 return kelvin - 273.15;

const func float: fahrenheit (in float: kelvin) is

 return kelvin * 1.8 - 459.67;

const func float: rankine (in float: kelvin) is

 return kelvin * 1.8;

const proc: main is func

 local
   var float: kelvin is 0.0;
 begin
   write("Enter temperature in kelvin: ");
   readln(kelvin);
   writeln("K: " <& kelvin             digits 2 lpad 7);
   writeln("C: " <& celsius(kelvin)    digits 2 lpad 7);
   writeln("F: " <& fahrenheit(kelvin) digits 2 lpad 7);
   writeln("R: " <& rankine(kelvin)    digits 2 lpad 7);
 end func;</lang>
Output:
Enter temperature in kelvin: 21.0
K:   21.00
C: -252.15
F: -421.87
R:   37.80

Tcl

<lang tcl>proc temps {k} {

   set c [expr {$k - 273.15}]
   set r [expr {$k / 5.0 * 9.0}]
   set f [expr {$r - 459.67}]
   list $k $c $f $r

}</lang> Demonstrating: <lang tcl>puts -nonewline "Enter a temperature in K: " flush stdout lassign [temps [gets stdin]] k c f r puts [format "K: %.2f" $k] puts [format "C: %.2f" $c] puts [format "F: %.2f" $f] puts [format "R: %.2f" $r]</lang>

Output:
Enter a temperature in K: 21
K: 21.00
C: -252.15
F: -421.87
R: 37.80

XPL0

<lang XPL0>include c:\cxpl\codes; real K, C, F, R; [ChOut(0, ^K); K:= RlIn(0); C:= K - 273.15; ChOut(0, ^C); RlOut(0, C); CrLf(0); F:= 1.8*C + 32.0; ChOut(0, ^F); RlOut(0, F); CrLf(0); R:= F + 459.67; ChOut(0, ^R); RlOut(0, R); CrLf(0); ]</lang>

Output:
K 21
C -252.15000
F -421.87000
R   37.80000

zkl

<lang zkl>K:=ask(0,"Kelvin: ").toFloat(); println("K %.2f".fmt(K)); println("F %.2f".fmt(K*1.8 - 459.67)); println("C %.2f".fmt(K - 273.15)); println("R %.2f".fmt(K*1.8));</lang>

Output:
Kelvin: 373.15
K 373.15
F 212.00
C 100.00
R 671.67

ZX Spectrum Basic

<lang zxbasic>10 REM Translation of traditional basic version 20 INPUT "Kelvin Degrees? ";k 30 IF k <= 0 THEN STOP: REM A value of zero or less will end program 40 LET c = k - 273.15 50 LET f = k * 1.8 - 459.67 60 LET r = k * 1.8 70 PRINT k; " Kelvin is equivalent to" 80 PRINT c; " Degrees Celsius" 90 PRINT f; " Degrees Fahrenheit" 100 PRINT r; " Degrees Rankine" 110 GO TO 20</lang>