typedef struct
{
    int numerator;
    int denominator;
} Fraction;
   
int main(void)
{
    vector<Fraction> fractions = calcRatios(1000);
    std::sort(
        fractions.begin(), 
        fractions.end(), 
        [](Fraction a, Fraction b){
            // Because of how the fractions are generated, 1/0 is in the vector
            long double ld_a = (a.denominator != 0) ? a.numerator/a.denominator : __LDBL_MAX__,
                        ld_b = (b.denominator != 0) ? b.numerator/b.denominator : __LDBL_MAX__;
            return ld_a < ld_b;
        }
    );

    ofstream test("test.txt");
    for(Fraction fraction: fractions)
        test << setw(4) << setfill('0') << fraction.numerator << ",";
    test << "n";
    for(Fraction fraction: fractions)
        test << setw(4) << setfill('0') << fraction.denominator << ",";
    test.close();
}

I’m generating fractions, which are then sorted and printed into “test.txt.”

The screenshot above is test.txt. Row 1 are the numerators, Row 2 are the denominators. Each entry is padded with 0s to align them. As you can see on the boxed portions, they’re not actually sorted. What am I doing wrong?