C Program to Calculate Difference Between Two Time Periods

To calculate the difference between two time periods in a C program, you can use structures to represent time and perform the subtraction operation. Here's a C program that calculates the difference between two time periods:

#include <stdio.h>

// Define a structure to represent time
struct Time {
    int hours;
    int minutes;
    int seconds;
};

// Function to calculate the difference between two time periods
void calculateTimeDifference(struct Time t1, struct Time t2, struct Time *difference) {
    int seconds1, seconds2, diff_seconds;

    // Convert both times to seconds
    seconds1 = t1.hours * 3600 + t1.minutes * 60 + t1.seconds;
    seconds2 = t2.hours * 3600 + t2.minutes * 60 + t2.seconds;

    // Calculate the difference in seconds
    diff_seconds = seconds1 - seconds2;

    // Convert the difference in seconds back to hours, minutes, and seconds
    difference->hours = diff_seconds / 3600;
    difference->minutes = (diff_seconds % 3600) / 60;
    difference->seconds = diff_seconds % 60;
}

int main() {
    struct Time startTime, endTime, timeDifference;

    // Input start time
    printf("Enter the start time (hours minutes seconds): ");
    scanf("%d %d %d", &startTime.hours, &startTime.minutes, &startTime.seconds);

    // Input end time
    printf("Enter the end time (hours minutes seconds): ");
    scanf("%d %d %d", &endTime.hours, &endTime.minutes, &endTime.seconds);

    // Calculate the time difference
    calculateTimeDifference(startTime, endTime, &timeDifference);

    // Display the time difference
    printf("Time Difference: %02d:%02d:%02d\n", timeDifference.hours, timeDifference.minutes, timeDifference.seconds);

    return 0;
} 

In this program, we use a structure Time to represent a time period with three components: hours, minutes, and seconds.

The calculateTimeDifference function takes two Time structures (for the start and end times) and a pointer to a Time structure (to store the difference). It calculates the difference in seconds and then converts it back to hours, minutes, and seconds.

In the main function, we:

1. Input the start time and end time from the user.

2. Call the calculateTimeDifference function to compute the difference between the two times.

3. Display the calculated time difference in the format HH:MM:SS.

Here's an example of how the program works:

Enter the start time (hours minutes seconds): 10 15 30
Enter the end time (hours minutes seconds): 12 30 45
Time Difference: 02:15:15 

In this example, the program calculates the time difference between 10:15:30 and 12:30:45, and the result is 2 hours, 15 minutes, and 15 seconds.