Some of Sunday's edits have been lost. The edits from Saturday that were reverted have been restored. Site is now hosted on prgmr.com. Thank you for your patience. This notice will be removed one week from posting. --Michael Mol 18:12, 7 March 2010 (UTC)
User input/Text
From Rosetta Code
See also: User Input - graphical
[edit] Ada
Works with: GCC version 4.1.2
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;
The functions above may be called as shown below
My_String : String := Get_String;
My_Integer : Integer := Get_Integer;
[edit] ALGOL 68
print("Enter a string: ");
STRING s := read string;
print("Enter a number: ");
INT i := read int;
~
[edit] AutoHotkey
[edit] Windows console
DllCall("AllocConsole")
FileAppend, please type something`n, CONOUT$
FileReadLine, line, CONIN$, 1
msgbox % line
FileAppend, please type '75000'`n, CONOUT$
FileReadLine, line, CONIN$, 1
msgbox % line
[edit] Input Command
this one takes input regardless of which application has focus.
TrayTip, Input:, Type a string:
Input(String)
TrayTip, Input:, Type an int:
Input(Int)
TrayTip, Done!, Input was recieved.
Msgbox, You entered "%String%" and "%Int%"
ExitApp
Return
Input(ByRef Output)
{
Loop
{
Input, Char, L1, {Enter}{Space}
If ErrorLevel contains Enter
Break
Else If ErrorLevel contains Space
Output .= " "
Else
Output .= Char
TrayTip, Input:, %Output%
}
}
[edit] AWK
This demo shows a same-line prompt, and that the integer i becomes 0 if the line did not parse as an integer.
~/src/opt/run $ awk 'BEGIN{printf "enter a string: "}{s=$0;i=$0+0;print "ok,"s"/"i}'
enter a string: hello world
ok,hello world/0
75000
ok,75000/75000
[edit] BASIC
Works with: QuickBasic version 4.5
INPUT "Enter a string: ", s$ 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
[edit] 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: "
^,_ & @
[edit] 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;
}
[edit] C++
Works with: g++
#include <iostream>
#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
getline(cin, string_input);
Note: if a numeric input operation fails, the value is not stored for that operation, plus the fail bit is set, which causes all future stream operations to be ignored (e.g. if a non-integer is entered for the first input above, then nothing will be stored in either the integer and the string). A more complete program would test for an error in the input (with if (!cin) // handle error) after the first input, and then clear the error (with cin.clear()) if we want to get further input.
Alternatively, we could read the input into a string first, and then parse that into an int later.
[edit] 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();
}
}
}
[edit] Clojure
(import '(java.util Scanner))
(def scan (Scanner. *in*))
(def s (.nextLine scan))
(def n (.nextInt scan))
[edit] Common Lisp
(format t "Enter some text: ")
(let ((s (read-line)))
(format t "You entered ~s~%" s))
(format t "Enter a number: ")
(let ((n (read)))
(if (numberp n)
(format t "You entered ~d.~%" n)
(format t "That was not a number.")))
[edit] D
import tango.io.Console;
import Integer = tango.text.convert.Integer;
void main() {
int num;
char[] word;
Cout("Enter an integer:")();
num = Integer.parse(Cin.get());
Cout("Enter a string:")();
word = Cin.get();
}
[edit] 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: ").
[edit] Factor
"Enter a string: " write
readln
"Enter a number: " write
readln string>number
[edit] FALSE
FALSE has neither a string type nor numeric input. Shown instead are routines to parse and echo a word and to parse and interpret a number using the character input command (^).
[[^$' =~][,]#,]w:
[0[^'0-$$9>0@>|~][\10*+]#%]d:
w;! d;!.
[edit] Forth
[edit] Input a string
: INPUT$ ( n -- addr n )
PAD SWAP ACCEPT
PAD SWAP ;
[edit] 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.
Works with: 4tH
: input#
begin
refill drop bl parse-word ( a n)
number error? ( n f)
while ( n)
drop ( --)
repeat ( n)
;
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 ;
[edit] Fortran
Works with: Fortran version 90 and later
character(20) :: s
integer :: i
print*, "Enter a string (max 20 characters)"
read*, s
print*, "Enter the integer 75000"
read*, i
[edit] Groovy
word = System.in.readLine()
num = System.in.readLine().toInteger()
[edit] Haskell
import System.IO (hFlush, stdout)
main = do
putStr "Enter a string: "
hFlush stdout
str <- getLine
putStr "Enter an integer: "
hFlush stdout
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. Note also: Haskell doesn't automatically flush stdout when doing input, so explicit flushes are necessary.
[edit] J
require 'misc' NB. load system script
prompt 'Enter string: '
0".prompt 'Enter 75000: '
Both of these sentences return the user provided input. But this implementation implements no error checking: For example, if a different number is entered at the second prompt, it will be used instead of 75000.
[edit] 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;
public class GetInput {
public static void main(String[] args) {
Scanner stdin = new Scanner(System.in);
String string = stdin.nextLine();
int number = stdin.nextInt();
}
}
[edit] JavaScript
Works with: JScript and only with cscript.exe
WScript.Echo("Enter a string");
var str = WScript.StdIn.ReadLine();
var val = 0;
while (val != 75000) {
WScript.Echo("Enter the integer 75000");
val = parseInt( WScript.StdIn.ReadLine() );
}
Works with: SpiderMonkey
print("Enter a string");
var str = readline();
var val = 0;
while (val != 75000) {
print("Enter the integer 75000");
val = parseInt( readline() );
}
[edit] Logo
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
[edit] Lua
print('Enter a string: ')
s = io.stdin:read()
print('Enter a number: ')
i = tonumber(io.stdin:read())
[edit] Mathematica
mystring = InputString["give me a string please"];
myinteger = Input["give me an integer please"];
[edit] Metafont
string s;
message "write a string: ";
s := readstring;
message s;
message "write a number now: ";
b := scantokens readstring;
if b = 750:
message "You've got it!"
else:
message "Sorry..."
fi;
end
If we do not provide a number in the second input, Metafont will complain. (The number 75000 was reduced to 750 since Metafont biggest number is near 4096).
[edit] mIRC Scripting Language
alias askmesomething {
echo -a You answered: $input(What's your name?, e)
}
[edit] 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.
[edit] newLISP
Works with: newLISP version 9.0
(print "Enter an integer: ")
(set 'x (read-line))
(print "Enter a string: ")
(set 'y (read-line))
[edit] 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
[edit] Octave
% read a string ("s")
s = input("Enter a string: ", "s");
% read a GNU Octave expression, which is evaluated; e.g.
% 5/7 gives 0.71429
i = input("Enter an expression: ");
% parse the input for an integer
printf("Enter an integer: ");
ri = scanf("%d");
% show the values
disp(s);
disp(i);
disp(ri);
[edit] Oz
declare
StdIn = {New class $ from Open.file Open.text end init(name:stdin)}
StringInput
Num = {NewCell 0}
in
{System.printInfo "Enter a string: "}
StringInput = {StdIn getS($)}
for until:@Num == 75000 do
{System.printInfo "Enter 75000: "}
Line = {StdIn getS($)}
in
Num := try {String.toInt Line} catch _ then 0 end
end
[edit] Pascal
program UserInput(input, output);
var i : Integer;
s : String;
begin
write('Enter an integer: ');
readln(i);
write('Enter a string: ');
readln(s)
end.
[edit] Perl
Works with: Perl version 5.8.8
#!/usr/bin/perl
my $string = <>; # equivalent to readline(*STDIN)
my $integer = <>;
[edit] PHP
Works with: CLI SAPI
#!/usr/bin/php
<?php
$string = fgets(STDIN);
$integer = (int) fgets(STDIN);
[edit] Pike
int main(){
write("Enter a String: ");
string str = Stdio.stdin->gets();
write("Enter 75000: ");
int num = Stdio.stdin->gets();
}
[edit] PL/I
declare s character (100) varying;
declare k fixed decimal (15);
put ('please type a string:');
get edit (s) (L);
put skip list (s);
put skip list ('please type the integer 75000');
get list (k);
put skip list (k);
put skip ist ('Thanks');
[edit] 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();
[edit] 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.
[edit] PowerShell
$string = Read-Host "Input a string"
$number = Read-Host "Input a number"
[edit] PureBasic
If OpenConsole()
; Declare a string and a integer to be used
Define txt.s, num.i
Print("Enter a string: ")
txt=Input()
Repeat
Print("Enter the number 75000: ")
num=Val(Input()) ; Converts the Input to a Value with Val()
Until num=75000
; Check that the user really gives us 75000!
Print("You made it!")
Delay(3000): CloseConsole()
EndIf
[edit] Python
[edit] 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: ")
[edit] 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.
[edit] R
Works with: R version 2.81
stringval <- readline("String: ")
intval <- as.integer(readline("Integer: "))
[edit] Raven
'Input a string: ' print expect as str
'Input an integer: ' print expect 0 prefer as num
[edit] REBOL
rebol [
Title: "Textual User Input"
Author: oofoe
Date: 2009-12-07
URL: http://rosettacode.org/wiki/User_Input_-_text
]
s: n: ""
; Because I have several things to check for, I've made a function to
; handle it. Note the question mark in the function name, this convention
; is often used in Forth to indicate test of some sort.
valid?: func [s n][
error? try [n: to-integer n] ; Ignore error if conversion fails.
all [0 < length? s 75000 = n]]
; I don't want to give up until I've gotten something useful, so I
; loop until the user enters valid data.
while [not valid? s n][
print "Please enter a string, and the number 75000:"
s: ask "string: "
n: ask "number: "
]
; It always pays to be polite...
print rejoin [ "Thank you. Your string was '" s "'."]
Output:
Please enter a string, and the number 75000: string: This is a test. number: ksldf Please enter a string, and the number 75000: string: number: 75000 Please enter a string, and the number 75000: string: Slert... number: 75000 Thank you. Your string was 'Slert...'.
[edit] REXX
do until i = 75000
say "Input 75000"
pull i
end
[edit] 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
[edit] 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)
[edit] Slate
print: (query: 'Enter a String: ').
[| n |
n: (Integer readFrom: (query: 'Enter an Integer: ')).
(n is: Integer)
ifTrue: [print: n]
ifFalse: [inform: 'Not an integer: ' ; n printString]
] do.
[edit] Smalltalk
'Enter a number: ' display.
a := stdin nextLine asInteger.
'Enter a string: ' display.
b := stdin nextLine.
[edit] SNOBOL4
output = "Enter a string:"
str = trim(input)
output = "Enter an integer:"
int = trim(input)
output = "String: " str " Integer: " int
end
[edit] Standard ML
print "Enter a string: ";
let val str = valOf (TextIO.inputLine TextIO.stdIn) in (* note: this keeps the trailing newline *)
print "Enter an integer: ";
let val num = valOf (TextIO.scanStream (Int.scan StringCvt.DEC) TextIO.stdIn) in
print (str ^ Int.toString num ^ "\n")
end
end
[edit] 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 -strict $num]} then { ...do something here...}
If the requirement is to prompt until the user enters the integer 75000, then:
set input 0
while {$input != 75000} {
puts -nonewline "enter the number '75000': "
flush stdout
set input [gets stdin]
}
Of course, it's nicer to wrap the primitives in a procedure:
proc question {var message} {
upvar 1 $var v
puts -nonewline "$message: "
flush stdout
gets stdin $v
}
question name "What is your name"
question task "What is your quest"
question doom "What is the air-speed velocity of an unladen swallow"
[edit] TI-89 BASIC
This program leaves the requested values in the global variables s and integer.
Prgm
InputStr "Enter a string", s
Loop
Prompt integer
If integer ≠ 75000 Then
Disp "That wasn't 75000."
Else
Exit
EndIf
EndLoop
EndPrgm
[edit] 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
[edit] UNIX Shell
Works with: Debian Almquish SHell
#!/bin/sh
read STRING
read INTEGER
Works with: Bourne Again SHell
#!/bin/bash
read STRING
read INTEGER
[edit] Vedit macro language
Get_Input(1, "Enter a string: ")
#2 = Get_Num("Enter a number: ")
[edit] Visual Basic .NET
Platform: .NET
Works with: Visual Basic .NET version 9.0+
[edit] Input an Integer
Dim i As Integer
Console.WriteLine("Enter an Integer")
i = Console.ReadLine()
[edit] Input an Integer With Error Handling
Dim i As Integer
Dim iString As String
Console.WriteLine("Enter an Integer")
iString = Console.ReadLine()
Try
i = Convert.ToInt32(iString)
Catch ex As Exception
Console.WriteLine("This is not an Integer")
End Try
[edit] Input a String
Dim i As String
Console.WriteLine("Enter a String")
i = Console.ReadLine()
