Constant output program [closed]

Question

I was wondering how one might go and produce a program that takes input from some kind of random source and uses it to produce constant output. An obvious way is, for example, to take an integer x and output x/x for 1, but that isn't too clever, is it? Therefore, the task is to write a program that outputs the same thing, no matter which input is given to it.

Specifications

• The program may assume that the input is either a number or a one line string (that is, valid characters are [a-z][A-z][0-9] and spaces). If you adopt one of those restrictions, specify which in your answer.
• The program must use the entered input in some way. To put it more formally, the contents of the variable that takes the input must be used afterwards in some calculation that affects the final variable to be printed.

The winner will be the most upvoted solution.

Answer 1

Python

This question is boring. I'd rather sleep.

from time import sleep
sleep(input())

Input a number.

Answer 2

GolfScript

~{.3*){.2%}{2/}until.@=!}do

This program will take a positive integer as input, and will output 1 unless the input is a counterexample to the Collatz conjecture. While the Collatz conjecture remains an open problem, it is known that there are no counterexamples below 5 × 2⁶⁰.

Answer 3

Perl

<>/0

produces for any input string:

Illegal division by zero at test5.pl line 1, <> line 1.

Answer 4

Ruby

def a(x)
  4
end

I somehow felt this was related:

Answer 5

Python

n=input()
p=37
print (n**p-n)%p

Takes an integer input, and always outputs 0. Uses Fermat's little theorem, which states that n^p == n mod p.

Answer 6

J

=

Usage:

   =10
1

Always outputs 1.

Or how about an unhappy smiley verb:

{:0[

Usage:

   {:0[ 147
0

Always ouputs 0.

Answer 7

C

This program reads an integer from stdin and then prints that integer, right?

main() {
    int i;
    printf("%d\n", scanf("%d", &i));
}

Well, no. It just prints 1.

The input must be an integer though (otherwise it may output 0 or -1), which proves that the program "uses" the input.

Answer 8

Javascript

var input = ~~prompt("Input an integer!");
if(Math.abs(input)<=Math.pow(2,31))
  console.log("It's too small! (not bigger than 2^31 = "+Math.pow(2,31)+")");
else console.log("It's quite big!");

Though JS can represent any integer between ±9,007,199,254,740,992, it will always print

It's too small! (not bigger than 2^31 = 2147483648)

because bitwise operation is performed in range of 32bit.

Answer 9

Python 2

x=input()
print x^x

Only accepts integers. always outputs 0 by xoring itself

Answer 10

Ruby:

p !gets

Always outputs false. gets takes user input, ! negates that and since strings are truthy, the result will be false.

Answer 11

APL

⍴⍣≡

⍴ is the shape function, ⍴⍣≡ is the fixpoint of the shape function.

All APL values have a shape. Say, a 4x6x8 array has shape 4 6 8; a scalar (like 3) has shape ⍬ (no dimensions). Therefore, ⍴ always returns a one-dimensional list. This means that applying the output of ⍴ to ⍴ will always get you a one-dimensional list with one number in it. That means that applying ⍴ again will always get you a one-dimensional list with the number 1 in it.

Therefore, ⍴ converges to 1; therefore ⍴⍣≡ will give 1 for all possible inputs.

Answer 12

Golfscript

.=

Accepts any input and always prints 1.

Answer 13

Python

def f(x):    
    return 0*x

Answer 14

JavaScript

var input = prompt("Input something!");

console.log(new Number(input) === 1);

Will always return false, even with the input 1

Answer 15

Golfscript (4 chars)

~1\?

Accepts an integer. Outputs 1.

Answer 16

Perl

$a=<>+1;for(1..length$a){$a=length$a}print$a

This program does use the input number, and it always prints 1.

Answer 17

Python

print float("inf")*sum(map(ord,raw_input()))

Always returns 'infinity'.

Answer 18

Q

Returns 1. Where no parameters are declared, Q implicitly uses x,y& z where appropriate. I think this satisfies the second condition...

{1}

Answer 19

Python

print input()*0

Answer 20

Python

This one works for numbers only.
I can't prove that it works for all numbers (can anyone?), but it prints "False" for all cases I've tested.
EDIT: Fixed a bug in the last line.

p=lambda x:x>1 and (i*i>x for i in xrange(2,x+1) if x%i==0 or i*i>x).next()
q=lambda x:(i<x for i in xrange(2,x+1) if p(i) and p(x-i) or i==x).next()
x = input()
print x%2==0 and x>2 and not q(x)

Explanation (for those who think my Python code is unclear):
p(x) tells you if x is a prime.
q(x) looks for two primes, whose some is x.
The program prints True if the number is even, greater than 2 and not the sum of 2 primes.
Please tell me if you find such a number.

Answer 21

C

Produces 1 (prints and returns) for every input. (Input being the number of command line args)

j;main(c){j=0;while(c){j+=c%2;c/=2;}return j^1?main(j):printf("%d",j);}

This program does the same #error 1 but cannot properly speaking be said to take input (unless you count the rest of the program after as input).

Answer 22

Python

print eval('42#'+raw_input())

Accepts any input

Answer 23

PostScript

This function takes one argument of any type, actively discards, and will always output ­, unless you didn't supply it with enough arguments (which I am going to define as being undefined behavior for this function), depending on the value of the argument. Here is its implementation:

/f {pop} def

This function will always take one more argument than is currently on the stack, so it will always output a stackunderflow error, depending on the input.

/f {clear pop} def

And here is a third, even more useful function, which I will define as having undefined behavior, depending on the number, types, and values of the arguments. Here is its implementation:

­

Answer 24

Common Lisp

(unless (read))

Always returns nil (unless you crash it with stupid input)

Answer 25

Clojure

(and(read-line)0)

Crudely equivalent to the prior common lisp submission, except that it makes no attempt to ensure that the line "read" is valid in any way shape or form. Compiled or interpreted, this program will read a single line and exit 0 in all cases.

Answer 26

Game Maker Language

if argument0 return argument0/argument0 else return argument0

It can be any script, just call script(argument) - it returns true if the number is not 0, else it returns false

If this was code golf, it would be if argument0 a=1 return a which is 25 characters when compiled with the option "Treat all uninitialized variables as value 0".

Answer 27

Brainf**k

Since the question is self-contradictory it's hard to give a serious answer, so here it is:

,[[->+<],]>[<->+<+>--<+>][->+>+[-]>+>+<<<<][->-<]+>[<->[-]]>[->--<----]+>[[---<->+<+>-]<->]>>[+>-<--]+>[[-]<->]<<[->-<-->+++>>>>>+<<<->+<<<+++++[>>++++++<<]]+>[<+>-]++>+<-<->>>>+<<<<->+<+>->>>[<]>[>]<[<[->-<]+>[<->[-]]<]+[>+>+>+>+<<---<<[-]]>>++<<[>>+[+<<<-]>>-<[<]+<<[<<->+]]>[->>+<<]>>[->+<]>[>+++++++++++<-]>[->+>+>+<<<]>[.>]

Accepts any string or number as input, always outputs "!!!". Have fun figuring out what it does.

Answer 28

C++

Accepts any input. Prints ASCII equivalent of each character entered:

#include <iostream>
#include <string>
using namespace std;

int main() {
  string s;
  cout << "Enter a string: ";
  cin >> s;

  cout << "ASCII characters of input:\n";

  for (int i = 0; i < s.size(); i++)
    cout << s[i] << ": " << int(s[i]) << endl;

  return 0;
}

Answer 29

Befunge

&@

always returns nothing.

---

And a less pointless version:

&>:v
 -
 ^1_.@

Always returns 0