User Input

From Rosetta Code
Task
User Input
You are encouraged to solve this task according to the task description, using any language you may know.

In this task, the goal is to input a string and the integer 75000, from the normal user interface.

Text Terminal

Ada

Works with: GCC version 4.1.2

<lang ada>

  function Get_String return String is
    Line : String (1 .. 1_000);
    Last : Natural;
  begin
    Get_Line (Line, Last);
    return Line (1 .. Last);
  end Get_String;
  function Get_Integer return Integer is
    S : constant String := Get_String;
  begin
    return Integer'Value (S);
    --  may raise exception Constraint_Error if value entered is not a well-formed integer
  end Get_Integer;
</lang>

The functions above may be called as shown below <lang ada>

  My_String  : String  := Get_String;
  My_Integer : Integer := Get_Integer;

</lang>

ALGOL 68

print("Enter a string: ");
STRING s := read string;
print("Enter a number: ");
INT i := read int;
~

BASIC

Works with: QuickBasic version 4.5
 INPUT "Enter a string: ", s$
 INPUT "Enter a number: ", i%
Works with: FreeBASIC
 dim s as string
 dim i as integer
 
 input "Enter a string: ", s
 input "Enter the integer 75000: ", i

Befunge

This prompts for a string and pushes it to the stack a character at a time (~) until end of input (-1).

<>:v:"Enter a string: "
 ^,_ >~:1+v
     ^    _@

Numeric input is easier, using the & command.

<>:v:"Enter a number: "
 ^,_ & @

C

Works with: gcc
#include <stdio.h>
int main(int argc, char* argv[])
{
        int input;
        if((scanf("%d", &input))==1)
        {
                printf("Read in %d\n", input);
                return 1;
        }
        return 0;
}

C++

Works with: g++
#include <iostream>
#include <istream>
#include <ostream>
#include <string>
using namespace std;

int main()
{
     // while probably all current implementations have int wide enough for 75000, the C++ standard
     // only guarantees this for long int.
     long int integer_input;
     string string_input;
     cout << "Enter an integer:  ";
     cin >> integer_input;
     cout << "Enter a string:  ";
     cin >> string_input;
     return 0;
}

Note: The program as written above only reads the string up to the first whitespace character. To get a complete line into the string, replace

cin >> string_input;

with

readline(cin, string_input);

C#

 using System;
 
 namespace C_Sharp_Console {
 
     class example {
 
         static void Main() {
             string word;
             int num;
             
             Console.Write("Enter an integer: ");
             num = Console.Read();
             Console.Write("Enter a String: ");
             word = Console.ReadLine();
         }
     }
 }

Erlang

{ok, [String]} = io:fread("Enter a string: ","~s").
{ok, [Number]} = io:fread("Enter a number: ","~d").

Alternatively, you could use io:get_line to get a string:

String = io:get_line("Enter a string: ").

Forth

Input a string

: INPUT$ ( n -- addr n )
   PAD SWAP ACCEPT
   PAD SWAP ;

Input a number

The only ANS standard number interpretation word is >NUMBER ( ud str len -- ud str len ), which is meant to be the base factor for more convenient (but non-standard) parsing words.

: INPUT# ( -- u true | false )
  0. 16 INPUT$ DUP >R
  >NUMBER NIP NIP 
  R> <> DUP 0= IF NIP THEN ;
Works with: GNU Forth
: INPUT# ( -- n true | d 1 | false )
   16 INPUT$ SNUMBER? ;
Works with: Win32Forth
: INPUT# ( -- n true | false )
   16 INPUT$ NUMBER? NIP
   DUP 0= IF NIP THEN ;

Note that NUMBER? always leaves a double result on the stack. INPUT# returns a single precision number. If you desire a double precision result, remove the NIP.

Here is an example that puts it all together:

: TEST
  ." Enter your name: " 80 INPUT$ CR
  ." Hello there, " TYPE CR
  ." Enter a number: " INPUT# CR
  IF   ." Your number is " .
  ELSE ." That's not a number!" THEN CR ;

Groovy

word = System.in.readLine()
num = System.in.readLine().toInteger()


Haskell

main = do
    putStr "Enter a string: "
    str <- getLine
    putStr "Enter an integer: "
    num <- readLn :: IO Int 
    putStrLn $ str ++ (show num)

Note: :: IO Int is only there to disambiguate what type we wanted from read. If num were used in a numerical context, its type would have been inferred by the interpreter/compiler.

Java

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class GetInput {
    public static void main(String[] args) throws Exception {
        BufferedReader sysin = new BufferedReader(new InputStreamReader(System.in));
        int number = Integer.parseInt(sysin.readLine());
        String string = sysin.readLine();
    }
}

or

Works with: Java version 1.5/5.0+
import java.util.Scanner;

Scanner stdin = new Scanner(System.in);
String string = stdin.nextLine();
int number = stdin.nextInt();

Logo literals may be read from a line of input from stdin as either a list or a single word.

make "input readlist   ; in: string 75000
show map "number? :input  ; [false true]

make "input readword   ; in: 75000
show :input + 123       ; 75123 
make "input readword   ; in: string 75000
show :input             ; string 75000

mIRC Scripting Language

alias askmesomething {
  echo -a You answered: $input(What's your name?, e)
}

Modula-3

MODULE Input EXPORTS Main;

IMPORT IO, Fmt;

VAR string: TEXT;
    number: INTEGER;

BEGIN
  IO.Put("Enter a string: ");
  string := IO.GetLine();
  IO.Put("Enter a number: ");
  number := IO.GetInt();
  IO.Put("You entered: " & string & " and " & Fmt.Int(number) & "\n");
END Input.

newLISP

Works with: newLISP version 9.0
(print "Enter an integer: ")
(set 'x (read-line))
(print "Enter a string: ")
(set 'y (read-line))

OCaml

<lang ocaml>print_string "Enter a string: "; let str = read_line () in

 print_string "Enter an integer: ";
 let num = read_int () in
   Printf.printf "%s%d\n" str num</lang>

Pascal

program UserInput(input, output);
var i : Integer;
    s : String;
begin
 write('Enter an integer: ');
 readln(i);
 write('Enter a string: ');
 readln(s)
end.

Perl

Works with: Perl version 5.8.8
#!/usr/bin/perl

my $string = <>; # equivalent to readline(*STDIN)
my $integer = <>;

PHP

Works with: CLI SAPI
#!/usr/bin/php
<?php
$string = fgets(STDIN);
$integer = (int) fgets(STDIN);

Pop11

;;; Setup item reader
lvars itemrep = incharitem(charin);
lvars s, c, j = 0;
;;; read chars up to a newline and put them on the stack
while (charin() ->> c) /= `\n` do j + 1 -> j ; c endwhile;
;;; build the string
consstring(j) -> s;
;;; read the integer
lvars i = itemrep();

PostScript

Works with: PostScript version level-2
%open stdin for reading (and name the channel "kbd"):
/kbd (%stdin) (r) file def
%make ten-char buffer to read string into:
/buf (..........) def
%read string into buffer:
kbd buf readline

At this point there will be two items on the stack: a boolean which is "true" if the read was successful and the string that was read from the kbd (input terminates on a <return>). If the length of the string exceeds the buffer length, an error condition occurs (rangecheck). For the second part, the above could be followed by this:

%if the read was successful, convert the string to integer:
{cvi} if

which will read the conversion operator 'cvi' (convert to integer) and the boolean and execute the former if the latter is true.

PowerShell

$string = Read-Host "Input a string"
$number = Read-Host "Input a number"

Python

Input a string

  string = raw_input("Input a string: ")

In Python 3.0, raw_input will be renamed to input(). The Python 3.0 equivalent would be

  string = input("Input a string: ")

Input a number

While input() gets a string in Python 3.0, in 2.x it is the equivalent of eval(raw_input(...)). Because this runs arbitrary code, and just isn't nice, it is being removed in Python 3.0. raw_input() is being changed to input() because there will be no other kind of input function in Python 3.0.

  number = input("Input a number: ")  # Deprecated, please don't use.

Python 3.0 equivalent:

  number = eval(input("Input a number: ")) # Evil, please don't use.

The preferred way of getting numbers from the user is to take the input as a string, and pass it to any one of the numeric types to create an instance of the appropriate number.

  number = float(raw_input("Input a number: "))

Python 3.0 equivalent:

  number = float(input("Input a number: "))

float may be replaced by any numeric type, such as int, complex, or decimal.Decimal. Each one varies in expected input.

Raven

'Input a string: '   print expect as str
'Input an integer: ' print expect 0 prefer as num

Ruby

Works with: Ruby version 1.8.4
print "Enter a string: "
s = gets
print "Enter an integer: "
i = gets.to_i   # If string entered, will return zero
puts "String  = " + s
puts "Integer = " + i.to_s

Scheme

The read procedure is R5RS standard, inputs a scheme representation so, in order to read a string, one must enter "hello world"

 (define str (read))
 (define num (read))
 (display "String = ") (display str)
 (display "Integer = ") (display num)

Tcl

Like LISP, there is no concept of a "number" in TCL - the only real variable type is a string (whether a string might represent a number is a matter of interpretation of the string in a mathematical expression at some later time). Thus the input is the same for both tasks:

 set str [gets stdin]
 set num [gets stdin]

possibly followed by something like

 if {![string is integer $num]} then { ...do something here...}

Toka

needs readline
." Enter a string: " readline is-data the-string
." Enter a number: " readline >number [ ." Not a number!" drop 0 ] ifFalse is-data the-number
the-string type cr
the-number . cr

UNIX Shell

#!/bin/sh

read STRING
read INTEGER

Works with: Bourne Again SHell
#!/bin/bash

read STRING
read INTEGER

Vedit macro language

Get_Input(1, "Enter a string: ")
#2 = Get_Num("Enter a number: ")

GUI

AppleScript

set input to text returned of (display dialog "Enter text:" default answer "")
set input to text returned of (display dialog "Enter a number:" default answer "") as integer

Java

Library: Swing
import javax.swing.*;

public class GetInputSwing {
    public static void main(String[] args) throws Exception {
        int number = Integer.parseInt(JOptionPane.showInputDialog ("Enter an Integer"));
        String string = JOptionPane.showInputDialog ("Enter a String");
    }
}

Python

Works with: Python version 2.5
Library: Tkinter
 import tkSimpleDialog
 
 number = tkSimpleDialog.askinteger("Integer", "Enter a Number")
 string = tkSimpleDialog.askstring("String", "Enter a String")

Tcl

Library: Tk
 # create entry widget:
 pack [entry .e1]
 # read its content:
 set input [.e get]

Alternatively, the content of the widget can be tied to a variable:

 pack [entry .e1 -textvar input]
 # show the content at any time by
 puts $input

The -validate option can be used to test the contents/edits of the widget at any time against any parameters (including testing string is integer when the user hits <Return> or such)

VBScript

 strUserIn = InputBox("Enter Data")
 Wscript.Echo strUserIn

Vedit macro language

Displays a dialog box with two input fields and default OK button. The values entered are stored in text registers 1 and 2. The value from 2nd field is then converted into numeric value. (Accepts integers or integer expressions.)

Dialog_Input_1(1, "`User Input example`,
                   `??Enter a string `,
                   `??Enter a number `") 
#2 = Num_Eval_Reg(2)