Calculating Difference Between Two Times Using C++

#include <iostream>
using namespace std;
struct time
{
    int sec, min, hr;
};
void timeDiff(struct time, struct time, struct time *);
int main()
{
    struct time  diff, t1, t2;
    cout << "Starting time" << endl;
    cout << "Insert hours, minutes and seconds respectively:\n";
    cin >> t1.hr >> t1.min >> t1.sec;
    cout << "\nStoppage time" << endl;
    cout << "Insert hours, minutes and seconds respectively:\n";
    cin >> t2.hr >> t2.min >> t2.sec;
    timeDiff(t1, t2, &diff);
    cout << endl << "Time Difference: " << t1.hr << ":" << t1.min << ":" << t1.sec;
    cout << " - " << t2.hr << ":" << t2.min << ":" << t2.sec;
    cout << " = " << diff.hr << ":" << diff.min << ":" << diff.sec;
    return 0;
}
void timeDiff(struct time t1, struct time t2, struct time *diff)
{
    if(t2.sec > t1.sec)
    {
        --t1.min;
        t1.sec += 60;
    }
    diff->sec = t1.sec - t2.sec;
    if(t2.min > t1.min)
    {
        --t1.hr;
        t1.min += 60;
    }
    diff->min = t1.min-t2.min;
    diff->hr = t1.hr-t2.hr;
}

Starting time
 Insert hours, minutes and seconds respectively:
 5
 32
 16

 Stoppage time
 Insert hours, minutes and seconds respectively:
 2
 42
 6

 Time Difference: 5:32:16 - 2:42:6 = 2:50:10

• A structure time is created and a structure variable t1 and t2 is created. Some variables are initialized in the structure int type: sec, min, hr.
• The user is requested to enter the starting time in hours, minutes, and seconds respectively. This information is saved in the structure variable t1.
• The user is requested to enter the stoppage time in hours, minutes and seconds respectively. This input is saved in the structure variable t2.
• A function timeDiff is created and called by reference in the main () function.
• This function is used to calculate the time difference. The result is displayed on the screen.