C 计算两个时间段差值的程序

#include <stdio.h>
struct TIME {
   int seconds;
   int minutes;
   int hours;
};
void differenceBetweenTimePeriod(struct TIME t1,
                                 struct TIME t2,
                                 struct TIME *diff);
int main() {
   struct TIME startTime, stopTime, diff;
   printf("Enter the start time. \n");
   printf("Enter hours, minutes and seconds: ");
   scanf("%d %d %d", &startTime.hours,
         &startTime.minutes,
         &startTime.seconds);
   printf("Enter the stop time. \n");
   printf("Enter hours, minutes and seconds: ");
   scanf("%d %d %d", &stopTime.hours,
         &stopTime.minutes,
         &stopTime.seconds);
   // Difference between start and stop time
   differenceBetweenTimePeriod(startTime, stopTime, &diff);
   printf("\nTime Difference: %d:%d:%d-", startTime.hours,
          startTime.minutes,
          startTime.seconds);
   printf("%d:%d:%d ", stopTime.hours,
          stopTime.minutes,
          stopTime.seconds);
   printf("= %d:%d:%d\n", diff.hours,
          diff.minutes,
          diff.seconds);
   return 0;
}
// Computes difference between time periods
void differenceBetweenTimePeriod(struct TIME start,
                                 struct TIME stop,
                                 struct TIME *diff) {
   while (stop.seconds > start.seconds) {
     --start.minutes;
      start.seconds += 60;
   }
   diff->seconds = start.seconds-stop.seconds;
   while (stop.minutes > start.minutes) {
     --start.hours;
      start.minutes += 60;
   }
   diff->minutes = start.minutes-stop.minutes;
   diff->hours = start.hours-stop.hours;
}

Enter the start time.
Enter hours, minutes and seconds: 13
34
55
Enter the stop time.
Enter hours, minutes and seconds: 8
12
15
Time Difference: 13:34:55-8:12:15 = 5:22:40