C Exercises: Get the fraction part from two given integers representing the numerator and denominator in string format

C Programming Mathematics: Exercise-7 with Solution

Write a C program to get the fraction part from two given integers representing the numerator and denominator in string format.

Example:
Input:
n = 3
d = 2

n = 4
d = 7
Output:
Fractional part: 1.5
Fractional part: 0.(571428)

Sample Solution:

C Code:

//Source: https://bit.ly/2KNsta8
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

char* fractionToDecimal(int numerator, int denominator) {
    char *p;
    int psz, n, *dec, dsz, x;
    long long num, den, k, f;
    int i, repeat_at;
    int neg = 0;
    
    psz = dsz = 100; n = x = 0;
    p = malloc(psz * sizeof(char));
    //assert(p);
    
    neg = ((numerator > 0 && denominator < 0) ||
           (numerator < 0 && denominator > 0)) ? 1 : 0;
    num = numerator;
    den = denominator;
    num = (num < 0) ? -num : num;
    den = (den < 0) ? -den : den;
    
    k = num / den;
    f = num % den;
    
    if (neg && (k || f)) p[n ++] = '-';
    
    n += sprintf(&p[n], "%lld", k);
    if (!f) {
        p[n] = 0;
        return p;
    }
    
    p[n ++] = '.';
    
    dec = malloc(dsz * sizeof(int));
    //assert(dec);
    
    repeat_at = -1;
    if (f < 0) f = -f;
    while (f) {
        for (i = 0; i < x; i += 2) {
            if (dec[i] == f) {
                repeat_at = i;
                goto done;
            }
        }
        if (x + 1 >= dsz) {
            dsz *= 2;
            dec = realloc(dec, dsz * sizeof(int));
            //assert(dec);
        }
        dec[x ++] = f;
        f *= 10;
        k = f / den;
        dec[x ++] = k;
        f = f % den;
    }
    
done:
    for (i = 0; i < x; i += 2) {
        if (n + 3 > psz) {
            psz *= 2;
            p = realloc(p, psz * sizeof(char));
            //assert(p);
        }
        if (repeat_at == i) {
            p[n ++] = '(';
        }
        p[n ++] = '0' + dec[i + 1];
    }
    if (repeat_at != -1) p[n ++] = ')';
    p[n ++] = 0;
    
    free(dec);
    
    return p;
}

int main(void)
{
    int n = 3;
    int d = 2;
    printf("\nn = %d, d = %d  ", n, d);
    printf("\nFractional part: %s ",fractionToDecimal(n, d));
    n = 4;
    d = 7;
    printf("\n\nn = %d, d = %d  ", n, d);
    printf("\nFractional part: %s ",fractionToDecimal(n, d));
    return 0;
}

Sample Output:

n = 3, d = 2  
Fractional part: 1.5 

n = 4, d = 7  
Fractional part: 0.(571428) 

Flowchart:

C Programming Code Editor:

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