Programming Example

C Program to Calculate Difference Between Two Time Periods

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💻 Practical Program

📘 Step by Step Learning

In this example, you'll learn to calculate the difference between two time periods using user defined - differenceBetweenTimePeriod function.

Program Code

#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 start time: \n");
    printf("Enter hours, minutes and seconds respectively: ");
    scanf("%d %d %d", &startTime.hours, &startTime.minutes, &startTime.seconds);

    printf("Enter stop time: \n");
    printf("Enter hours, minutes and seconds respectively: ");
    scanf("%d %d %d", &stopTime.hours, &stopTime.minutes, &stopTime.seconds);

    // Calculate the difference between the start and stop time period.
    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;
}

void differenceBetweenTimePeriod(struct TIME start, struct TIME stop, struct TIME *diff)
{
    if(stop.seconds > start.seconds){
        --start.minutes;
        start.seconds += 60;
    }

    diff->seconds = start.seconds - stop.seconds;
    if(stop.minutes > start.minutes){
        --start.hours;
        start.minutes += 60;
    }

    diff->minutes = start.minutes - stop.minutes;
    diff->hours = start.hours - stop.hours;
}

Output

Enter start time:
Enter hours, minutes and seconds respectively: 12
34
55
Enter stop time:
Enter hours, minutes and seconds respectively:8
12
15

TIME DIFFERENCE: 12:34:55 - 8:12:15 = 4:22:40

Explanation

In this example, you'll learn to calculate the difference between two time periods using user defined - differenceBetweenTimePeriod function.

In this program, user is asked to enter two time periods and these two periods are stored in structure variables startTime and stopTime respectively.

Then, the function differenceBetweenTimePeriod calculates the difference between the time periods and the result is displayed in main() function without returning it (Using call by reference technique).

How to learn from this program

First read the algorithm, then study the program code line by line. After that, compare the code with the output and finally go through the explanation. This approach helps learners understand both the logic and the implementation properly.

Practice suggestion

After understanding this example, try to rewrite the same program without looking at the code. Then change some values or logic and run it again. This helps improve confidence and keeps learners engaged on the page for longer.