Input/Output for lines of text

Input/Output for lines of text is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

This task has been flagged for clarification. Code on this page in its current state may be flagged incorrect once this task has been clarified. See this page's Talk page for discussion.

Task

The first line contains the number of lines to follow, followed by that number of lines of text on   STDIN.

Write to   STDOUT   each line of input by passing it to a method as an intermediate step. The code should demonstrate these 3 things.

Sample input with corresponding output

Input

3
hello
hello world
Pack my Box with 5 dozen liquor jugs 

Output

hello
hello world
Pack my Box with 5 dozen liquor jugs

Related tasks

•   Input/Output for Pairs of Numbers
•   File/Input and Output

ALGOL 68

Works with: ALGOL 68G version Any - tested with release 2.8.win32

<lang algol68># outputs line plus a newline # PROC show line = ( STRING line )VOID:

   print( ( line, newline ) );

1. copy the lines with an loop with an anonymous loop counter #
2. as the loop limit is evaluated only once, we can read the #
3. number of lines in the "TO" part #

TO ( INT n; read( ( n, newline ) ); n ) DO

   show line( ( STRING line; read( ( line, newline ) ); line ) )

OD </lang>

ALGOL W

<lang algolw>begin

   % outputs line on a newline %
   procedure showLine ( string(80) value line ); write( line );

   string(80) line;
   integer lineCount;
   read( lineCount );
   for lineNumber := 1 until lineCount do begin
       read( line );
       showLine( line )
   end for_lineNumber

end.</lang>

AWK

<lang AWK>

1. syntax: GAWK -f INPUT_OUTPUT_FOR_LINES_OF_TEXT.AWK

BEGIN {

   getline n
   while (i++ < n) {
     getline
     str = sprintf("%s%s\n",str,$0)
   }
   printf("%s",str)
   exit(0)

} </lang>

C

<lang C> /*Abhishek Ghosh, 20th March 2014, Rotterdam*/

1. include<stdlib.h>
2. include<stdio.h>

1. define LEN 100 /* Max string length */

int main() { char **list; int num, i;

scanf("%d",&num);

list = (char**)malloc(num*sizeof(char*));

for(i=0;i<num;i++) { list[i] = (char*)malloc(LEN*sizeof(char)); fflush(stdin); fgets(list[i],LEN,stdin); }

printf("\n");

for(i=0;i<num;i++) { printf("%s",list[i]); }

return 0; } </lang>

D

<lang d>void main() {

   import std.stdio, std.conv, std.string;

   enum doStuff = (in string line) => line.write;

   foreach (_; 0 .. readln.strip.to!uint)
       doStuff(readln.idup);

}</lang>

FreeBASIC

<lang freebasic>' FB 1.05.0 Win64

Sub printLines(lines() As String)

 For i As Integer = LBound(lines) To UBound(lines)
   Print lines(i)
 Next 

End Sub

Dim As UInteger n Input "", n Dim lines(1 To n) As String For i As Integer = 1 To n

 Line Input lines(i)

Next Print printLines lines() Sleep</lang>

Output:

3
hello
hello world
Pack my Box with 5 dozen liquor jugs

hello
hello world
Pack my Box with 5 dozen liquor jugs

Go

<lang go>package main

import ( "bufio" "fmt" "io" "log" "os" )

func main() { // Often we'd already have wrapped os.Stdin (or some other // io.Reader, like an *os.File) in a bufio.Reader by this point // and we'd use fmt.Fscanln() on that reader instead. var lines int n, err := fmt.Scanln(&lines) if n != 1 || err != nil { log.Fatal(err) }

// Use a bufio.Scanner. This uses a SplitFunc which we can choose // or provide our own that splits or otherwise pre-processes the // input into tokens however we like. // // Could also just use bufio.ReadString('\n') but a Scanner // with ScanLines matches (and removes) `\r?\n$` and is more // general purpose. // // Normally the loop would be just: // for scanner.Scan() { // // use scanner.Text() or scanner.Bytes() // } // and we'd loop until the scan indicated EOF. But for this task // we've got an explictly specified number of lines to read.

scanner := bufio.NewScanner(os.Stdin) scanner.Split(bufio.ScanLines) // not needed, this is the default for ; scanner.Scan() && lines > 0; lines-- { doStuff(scanner.Text()) } if err := scanner.Err(); err != nil { log.Fatal(err) } // Check for too few lines, normally not needed if lines > 0 { log.Fatalln("early", io.EOF) } }

func doStuff(line string) { fmt.Println(line) }</lang>

Haskell

<lang Haskell> doStuff = putStrLn main = getContents >>= mapM_ doStuff.tail.lines </lang>

J

[for number pairs links to this page.]

Example in bash. jconsole is on the PATH. <lang J> $ cat <<EOF | jconsole -js '2!:55@:0:@:(; (1!:2) 4:)@:(}. {.~ _ ". [: }: 0&{::)@:(<;.2)@:(1!:1) 3' > 3 > hello > hello world > Pack my Box with 5 dozen liquor jugs > EOF hello hello world Pack my Box with 5 dozen liquor jugs </lang> From the dictionary of j (DOJ) the data flow for the fork (f g h) is

5. Forks

As illustrated above, an isolated sequence of three verbs is called a fork; its monadic and dyadic cases are defined by:

  g
 / \
f   h
|   |
y   y

    g
   / \
  f   h
 / \ / \
x  y x  y

Reading from left to right

2!:55 is exit. 0: is a verb that returns 0 for any input. So now we know the script will terminate the j session with successful status.

What does it do before this? 1!:2 is "write to file", with left argument x as the data to write, and the right argument y specifies the file. 4: is a verb returning 4 for any input. File 4 is stdout.

;

is "raze". The fork

(; (1!:2) 4:)

writes data to stdout.

Good!

What is the data? (}. {.~ _ ". [: }: 0&{::) Because it has an odd number of verbs, this expresses a fork. And because {:: (fetch) is in the fork the right argument y is a vector of boxes. We know that the data has a number followed by some lines of text. Let's read the fork from left to right. The second verb, {. is "take" modified by the ~ "passive" adverb to swap arguments. Take uses a shape argument on left (x), and the data to take as y. Remembering the passive effect, the data to which take applies will be the beheaded vector of boxes---beheading removes the first line which is the number, and the fork to the right of {.~ computes the shape. Now looking at the fourth verb, ". (numbers) the default in case of error is _ (infinity meaning "all" when used along a shape dimension to take) and the data for numbers is the curtailed }: content of the first box (index origin 0). 0 is & (bonded also known as curried) to fetch. Curtailing removes the line feed. Since this gives a list of boxes, but we need to display literal data, raze "unboxes" one level of boxing. Good, if we have a list of boxed lines of input.

(<;.2)@:(1!:1) 3 (<;.2) is "< (box) ;. (cut) 2 . The 2 specifies the last item of the data as the fret, and to preserve the frets. (1!:1) 3 is "read stdin".

I chose to connect the parts into a single verb using @: (at).

With predefined verbs from standard profile we can write the simpler, more readable for native English speakers, and robust sentence which ensures a final linefeed fret and discards the frets with <;._2

exit@:0:@:(smoutput&>)@:(}. {.~ _ ". 0&{::)@:cutLF@:(1!:1) 3

Cheers! That's tacit j.

Java

<lang java>import java.util.Scanner;

public class Main { public static void doStuff(String word){ System.out.println(word); }

public static void main(String[] args) { Scanner in = new Scanner(System.in); int n = Integer.parseInt(in.nextLine()); //doesn't use nextInt() so nextLine doesn't just read newline character for(int i=0; i<n; i++){ String word = in.nextLine(); doStuff(word); } } }</lang>

Kotlin

<lang scala>// version 1.1.0

fun output(lines: Array<String>) = println(lines.joinToString("\n"))

fun main(args: Array<String>) {

   println("Enter the number of lines to be input followed by those lines:\n")
   val n = readLine()!!.toInt()
   val lines = Array<String>(n) { readLine()!! }
   println("\nThe lines you entered are:\n")
   output(lines)

}</lang>

Output:

Enter the number of lines to be input followed by those lines:

3
hello
hello world
Pack my Box with 5 dozen liquor jugs

The lines you entered are:

hello
hello world
Pack my Box with 5 dozen liquor jugs

Lua

<lang lua>function show (t)

   for _, line in pairs(t) do print(line) end

end

local lineTable, numLines = {}, io.read() for i = 1, numLines do table.insert(lineTable, io.read()) end show(lineTable)</lang>

PARI/GP

This task is not possible to implement directly in GP: for input() to take a string the user would have to wrap it in quotes (and escape quotes and newlines). One must use PARI: <lang c>#include <stdio.h>

1. include <stdlib.h>
2. include <pari/pari.h>

int main(void);

int main() {

 int i, n, s;
 GEN vec;
 
 // 1 MB stack, not using prime table
 pari_init(1000000, 0);
 
 scanf("%d", &n);
 GEN vec = cgetg(n+1, t_VEC);

 for (i = 1; i <= n; i++) {
   if (1 != scanf("%s", &s)) abort();
   gel(vec, i) = strtoGENstr(s);
 }

 pari_printf("%Ps", vec);
 return 0;

}</lang>

Perl 6

Short version:

<lang perl6>say get for ^get;</lang>

Verbose version:

<lang perl6>sub do-stuff ($line) {

   say $line;

}

my $n = +get; for ^$n {

   my $line = get;
   do-stuff $line;

}</lang>

Phix

<lang Phix>sequence stack = {} procedure push(string line)

   stack = append(stack,line)

end procedure

procedure pop_all()

   while length(stack) do
       puts(1,stack[1])
       stack = stack[2..$]
   end while

end procedure

string line = gets(0) sequence r = scanf(trim(line),"%d") if length(r)!=1 then

   puts(1,"input not a number\n")
   abort(0)

end if puts(1,"\n") for i=1 to r[1][1] do

   line = gets(0)
   push(line)
   puts(1,"\n")

end for puts(1,"===\n") pop_all()</lang>

Output:

(or more accurately the final state of the console)

3
one
two
three
===
one
two
three

PowerShell

<lang PowerShell>

1. script.ps1

$in = Get-Content $args[0] $in[1..($in.Count-1)]

1. ./script file.txt

</lang>

Python

<lang python>try: input = raw_input except: pass

def do_stuff(words): print(words)

linecount = int(input()) for x in range(linecount): line = input() do_stuff(line)</lang>

Racket

Translation of: Python

<lang Racket>#lang racket (define (do-stuff str)

 (displayln str))

(define line-count (read)) ;reads all kind of things

(define line-count (string->number ;only reads numbers

                   (string-trim
                    (read-line)))) 

(for ([i (in-range line-count)])

 (do-stuff (read-line)))</lang>

REXX

Programming note:   this method was chosen because the standard input may be identical to the standard output. <lang rexx>/*REXX program writes a number of lines from the default input file (C.L.). */

1. =linein() /*number of lines to be read from C.L. */

 do j=1  for #;   x.j=linein();  end  /*obtain input lines from stdin (C.L.).*/

call stuff /*call the STUFF subroutine for writes.*/ exit /*stick a fork in it, we're all done. */ /*────────────────────────────────────────────────────────────────────────────*/ stuff: do k=1 for #; call lineout ,x.k; end; return</lang>

Ruby

<lang ruby>def do_stuff(line)

 puts line

end

n = gets.to_i n.times do

 line = gets
 do_stuff(line)

end</lang>

Tcl

<lang tcl>proc do_stuff {line} {

   puts $line

}

foreach - [lrepeat [gets stdin] dummy] {

   do_stuff [gets stdin]

}</lang>

Ursa

<lang ursa>#

1. input/output for lines of text

1. get how many lines the user wants

decl int amount set amount (in int console)

1. loop through and get lines

decl string<> lines decl int i for (set i 0) (< i amount) (inc i)

       append (in string console) lines

end for

1. output the lines that the user entered

out endl console for (set i 0) (< i amount) (inc i)

       out lines endl console

end for </lang>

zkl

File ff.zkl: <lang zkl>numLines:=File.stdin.readln().strip().toInt(); text:=File.stdin.readln(numLines);

text.apply(File.stdout.write);</lang>

Output:

cat foo.txt | zkl ff
hello
hello world
Pack my Box with 5 dozen liquor jugs