Question

#include <stdio.h>
#include <stdlib.h>

int main (void)
{
    double f;

    printf ("What is the temperature in Fahrenheit?\n");
    scanf ("%d", &f);

    double x = (f-32)*(5/9);
    printf ("%d degrees Fahrenheit \n",f); 
    printf ("%d degrees Celsius",x); 
    system("PAUSE");  

    return 0;
}

The code seems to be printing the address of variable f instead of the value; it’s probably a syntax mistake.

Answer 1

In the printf() calls, %d should be %f (or perhaps %.2f):

printf ("%f degrees Farenheit \n",f); 
printf ("%f degrees Celsius",x); 

You also need to change:

double x = (f-32)*(5/9);

to

double x = (f-32)*(5.0/9);

In C, integer division (a division where both dividend and divisor are integer types) truncates, so 5/9 is always 0.

Also, the conversion specification for double with scanf() is %lf:

if (scanf("%lf", &f) != 1)
{
    fprintf(stderr, "Failed to read a valid floating point number\n");
    return(EXIT_FAILURE);
}