What of lack this program? (sorting with qsort, struct array)

What of lack this program? (sorting with qsort, struct array)

I'm create Fraction Struct Array Sorting program.
a little number (slightly under 1000) my program have good answer
but big number (slightly over 100000) my program have wrong answer
what's the problem?
this is my source and input data
#include <cstdlib>
#include <iostream>
using namespace std;
struct Fraction {
long long denominator;
long long numerator;
};
int compare(const void *a, const void *b) {
const struct Fraction *x = (Fraction *)a;
const struct Fraction *y = (Fraction *)b;
long long val = x->numerator * y->denominator - x->denominator *
y->numerator;
if (val == 0) {
return x->numerator - y->numerator > 0 ? 1 : -1;
} else {
return val;
}
}
Fraction setOfData[100000];
int numOfData, numOfK;
int main() {
cin >> numOfData >> numOfK;
for (int i = 0; i < numOfData; ++i) {
long long denominator;
long long numerator;
cin >> numerator >> denominator;
setOfData[i].numerator = numerator;
setOfData[i].denominator = denominator;
}
qsort(setOfData, numOfData, sizeof(Fraction), compare);
cout<< setOfData[numOfK - 1].numerator << ' ' << setOfData[numOfK -
1].denominator;
return 0;
}
and this is my input data
input data
7 4
56783 9765493
56786 9765492
56788 9765491
8888888 9765464
56687 9765395
56789 9765497
56785 9765496
sorting standard is non-decreasing
over input data my program print
8888888 9765464
56687 9765395
56783 9765493
56785 9765496
56786 9765492
56788 9765491
56789 9765497
what's the lack of this program? is it long long? or int? help me plz...