Calculate time in 24 hour format after a minutes using C++

#include <bits/stdc++.h>

using namespace std;

int main() {
    string s;
    cin >> s;
    int time;
    cin >> time;
    // extract the time to integer (from string)
    int hrs = stoi(s.substr(0, 2));
    int mins = stoi(s.substr(3, 2));
    // calculate the hours that will be added
    if (mins + time >= 60) {
        hrs += ((mins + time) / 60);
    }
    // calculate the final time
    hrs %= 24;
    mins = (mins + time) % 60;
    // convert the integer back to string
    // note: don't forget to place a colon(:) between the hours and minutes
    string ans = (hrs < 10 ? "0" + to_string(hrs) : to_string(hrs));
    ans += (":" + (mins < 10 ? "0" + to_string(mins) : to_string(mins)));
    cout << ans << '\n';
    return 0;
}