Question

How to get the difference between two dates in seconds with C

Answer 1

#include <stdio.h>
#include <time.h>

double difference_between_two_dates_in_seconds(struct tm date1, struct tm date2) {
    // Convert tm structures to time_t
    time_t time1 = mktime(&date1);
    time_t time2 = mktime(&date2);

    // Calculate the difference in seconds
    return difftime(time2, time1);
}

int main() {
    // Define two tm structures for the dates
    struct tm date1 = {0};
    struct tm date2 = {0};

    // Set the first date (e.g., 2025-01-01 00:00:00)
    date1.tm_year = 2025 - 1900; // Year since 1900
    date1.tm_mon = 0;            // Month (0-11, where 0 = January)
    date1.tm_mday = 12;          // Day of the month (1-31)
    date1.tm_hour = 0;
    date1.tm_min = 0;
    date1.tm_sec = 0;

    // Set the second date (e.g., 2025-01-13 12:00:00)
    date2.tm_year = 2025 - 1900;
    date2.tm_mon = 0;
    date2.tm_mday = 13;
    date2.tm_hour = 0;
    date2.tm_min = 0;
    date2.tm_sec = 0;

    printf("Difference in seconds: %.0f\n", difference_between_two_dates_in_seconds(date1, date2));

    return 0;
}

    
     
/*
run:
      
Difference in seconds: 86400
    
*/

 

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