Find the biggest fraction - struct question-CodePudding

I'm a computer science student and I did a test recently when I solved a cool question in a weird way but I think I succeeded. I'm ask before I appeal the test.

The question is to find the largest fraction from an array of struct.

The way I solved the question is by dividing into cases instead of a common denominator.

*** The Denominator always smaller then the numerator and the number is positive

*** After I run few end cases I did it wrong.

Thanks for all !

Fraction who_is_the_biggest(Fraction* a, int size) {
    Fraction max = a[0];
    int i;
    // find the max num
    for (i = 0; i < size; i  ) {
        if (a[i].whole > max.whole) {
            max = a[i];
        }
        // if a[i] == max do compare bewteen numerator and denominator
        if (a[i].whole == max.whole) {
            if (a[i].denominator == max.denominator && a[i].numerator > max.numerator) { // 3/4 & 2/4 --- > 3/4
                max = a[i];
            }
            else if (a[i].numerator == max.numerator && a[i].denominator < max.denominator) { // 3/5 & 3/6 --- > 3/5
                max = a[i];

            }
            else if (a[i].numerator != max.numerator && a[i].denominator != max.denominator) { // 2/100 & 3/4 --> 3/4 
                if (a[i].numerator > max.numerator && a[i].denominator < max.denominator) {
                    max = a[i];
                }

            }

        }
    }
    return max;
}

CodePudding user response：

You algorithm is completely wrong.

Test it 
int main(void)
{
    Fraction a[] = 
    {
        {.whole = 0, .numerator = 98, 101}, {.whole = 0, .numerator = 97, 99}
    };

    Fraction f = who_is_the_biggest(a, 2);
    printf("%d %d %f\n", f.numerator, f.denominator, ((double)a[0].numerator / a[0].denominator) / ((double)a[1].numerator / a[1].denominator));
}

https://godbolt.org/z/xPbWPzTWd

It returns a[0] but a[0] is smaller than a[1].

You need to find the smallest common denominator, then compare the fraction parts.

I did a test recently when I solved a cool question in a weird way but I think I succeeded

No, you did not succeed, do not appeal.