Why does the c variable always output 0?

Question

I am trying to write a program to convert fahrenheit to celsius. No matter what you input, c always outputs 0.

#include <stdio.h>

int main()
{
int f;
float c;

printf("Enter a temperature in fahrenheit: ");
scanf("%d", &f);

c = (f-32)*(5/9);

printf("%d fahrenheit is %.2f celsius.\n", f, c);
}

`(5/9)` is an integer calculation, result = 0. Try `(f-32)*5/9;`. — Weather Vane, Apr 16 '17 at 07:33
`f` is an int as well as `32`, `5` and `9`. You need explicit casting, that is `c = (f-32) * ((float)5/9)` or `c = (f-32) * (5.0/9)` (yea! `5.0` it's not the same as `5`!) — Bruno Zamengo, Apr 16 '17 at 07:35
Being used to standard measurement units: Do Farhenheit temperatures have no fraction? Why use an integer for Fahrenheit, but a `float` for Celsius? — too honest for this site, Apr 16 '17 at 07:36
https://stackoverflow.com/questions/2345902/division-result-is-always-zero — WhozCraig, Apr 16 '17 at 07:48

score 2 · Accepted Answer · answered Apr 16 '17 at 07:36

In integer math, 5/9 is 0, remainder 5. You want 5.0/9.0 instead.

In C, what you do with a result has no effect on how it's computed. So even though c is a float and you are storing the result of the math in a float, the math is still integer math because 5, 9, f and 32 are all integers.

Why does the c variable always output 0?

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