Reading fractions in C

Question

How do I read a fraction into C to do math with it? (The fraction will contain the slash symbol) For example, A user will input 3/12. (a string) The program will find the gc

Answer 1

Alright. I've got a different way. Use strtol which will return to you a pointer to the '/' to which you add 1 and call strtol again for the second half.

This is twice as fiddly as the first answer, halfway as fiddly as the second. :)

#include 
#include 

int main(){
    char *f = " 12/7 ";
    char *s;
    long n,d;
    n = strtol(f, &s, 10);
    d = strtol(s+1, NULL, 10);
    printf(" %ld/%ld \n", n, d);
    return 0;
}

To answer the rest of your question, you definitely need 2 variables if it's going to be a fraction. If you can use floating-point internally and the fractions are just a nice feature for user input, then you can go ahead and divide them and store the number in one variable.

double v;
v = (double)n / d;

The cast to double is there to force a floating-point divide upon the two integers.

If, on the other hand you're going to have a lot of fractions to work with, you may want to make a structure to hold them (an object, if you will).

struct frac {
    long num;
    long den;
};
struct frac f = { 12, 7 };
printf("%ld/%ld\n", f.num, f.den);