Time class: +, <= and << overloading

Three operators are overloaded for class Time:

• + adds two times (arithmetic, member function).
• <= compares two times (logical, member function).
• << prints a time. Its left operand is cout, an ostream object, so it cannot be a member of Time (it could only be a member of ostream, which we cannot modify). It is therefore written as a friend (non-member) function.

#include <iostream>
using namespace std;

class Time {
    int hr, min, sec;
public:
    Time(int h = 0, int m = 0, int s = 0) { hr = h; min = m; sec = s; }

    // arithmetic + : adds two times
    Time operator+(Time t) {
        Time r;
        r.sec = sec + t.sec;
        r.min = min + t.min + r.sec / 60;
        r.sec = r.sec % 60;
        r.hr  = hr + t.hr + r.min / 60;
        r.min = r.min % 60;
        return r;
    }

    // logical <= : true if this time is less than or equal to t
    bool operator<=(Time t) {
        int a = hr * 3600 + min * 60 + sec;
        int b = t.hr * 3600 + t.min * 60 + t.sec;
        return a <= b;
    }

    // stream insertion operator
    friend ostream& operator<<(ostream &out, Time &t) {
        out << t.hr << "h " << t.min << "m " << t.sec << "s";
        return out;
    }
};

int main() {
    Time t1(2, 45, 50), t2(1, 20, 30), t3;
    t3 = t1 + t2;
    cout << "t1 = " << t1 << endl;
    cout << "t2 = " << t2 << endl;
    cout << "t1 + t2 = " << t3 << endl;
    if (t1 <= t2) cout << "t1 <= t2" << endl;
    else          cout << "t1 > t2" << endl;
    return 0;
}

Output:

t1 = 2h 45m 50s
t2 = 1h 20m 30s
t1 + t2 = 4h 6m 20s
t1 > t2

Seconds 50 + 30 = 80 gives 1 min carry and 20 s; minutes 45 + 20 + 1 = 66 gives 1 hr carry and 6 min; hours 2 + 1 + 1 = 4.