C++程序编译不通过 错误提示也没明显提示 这个哪里出现错误了 请教

#include <iostream>
using namespace std;
struct travel_time
{
    int hours;
    int mins;
};
const int Mins_per_hr = 60;

travel_time sum (travel_time t1,travel_time t2);
void show_time (travel_time t);

int _tmain(int argc, _TCHAR* argv[])
{
    travel_time day1 = {5,45};
    travel_time day2 = {4,55};

    travel_time trip = sum (day1,day2);
    cout << "Two_day total: ";
    show_time (trip);

    travel_time day3 = {4,32};
    cout << "Three-day total: ";
    show_time (sum (trip,day3));

    system ("pause");
    return 0;
}
travel_time sum (travel_time t1,travel_time t2)
{
    travel_time total;

    total.mins = (t1.mins + t2.mins) % Mins_per_hr;
    total.hours = t1.hours + t2.hours + (t1.mins + t2.mins) / Mins_per_hr;


    return total;
}
void show (travel_time t)
{
    cout << t.hours << " hours, "
        << t.mins << " minutes\n";



}