PhanSo - NDDCoder

#include <iostream>
using namespace std;

int UCLN(int a, int b) {
    while (b) {
        int r = a % b;
        a     = b;
        b     = r;
    }
    return a;
}

int BCNN(int a, int b) {
    return a * b / UCLN(a, b);
}

class PhanSo {
private:
    int tuso, mauso;

public:
    PhanSo(int tuso, int mauso) : tuso(tuso), mauso(mauso) {
    }
    PhanSo() : PhanSo(0, 1) {
    }

PhanSo rutgon() {
        int ucln = UCLN(tuso, mauso);
        tuso /= ucln;
        mauso /= ucln;
        return *this;
    }

friend PhanSo operator+(const PhanSo& lps, const PhanSo& rps) {
        int mauchung = BCNN(lps.mauso, rps.mauso);
        int tuso =
            mauchung / lps.mauso * lps.tuso + mauchung / rps.mauso * rps.tuso;
        return PhanSo(tuso, mauchung).rutgon();
    }

friend istream& operator>>(istream& is, PhanSo& ps) {
        return is >> ps.tuso >> ps.mauso;
    }

friend ostream& operator<<(ostream& os, const PhanSo& ps) {
        return os << ps.tuso << "/" << ps.mauso;
    }
};

int main(int argc, char const* argv[]) {
    PhanSo ps1, ps2;
    cin >> ps1 >> ps2;
    cout << ps1 << " + " << ps2 << " = " << ps1 + ps2;
    return 0;
}