C Exercises: Convert a time_t object to calendar time expressed as local time

C Date Time: Exercise-7 with Solution

Write a program in C to convert a time_t object to calendar time expressed as local time.

Sample Solution:

C Code:

#define __STDC_WANT_LIB_EXT1__ 1
#include <stdio.h>
#include <time.h>

int main(void)
{
    // Get current time in seconds since epoch
    time_t t = time(NULL);

    // Print the calendar time expressed as local time and UTC time
    printf("\nThe calendar time expressed as a local Time is :");
    printf("\nUTC:   %s", asctime(gmtime(&t))); // Convert and print UTC time
    printf("local: %s\n", asctime(localtime(&t))); // Convert and print local time

#ifdef __STDC_LIB_EXT1__
    // Using secure versions of functions available in C11
    struct tm buf;
    char str[26];

    // Convert and print UTC time using secure version of functions
    asctime_s(str, sizeof str, gmtime_s(&t, &buf));
    printf("UTC:   %s", str);

    // Convert and print local time using secure version of functions
    asctime_s(str, sizeof str, localtime_s(&t, &buf));
    printf("local: %s", str);
#endif
}

Sample Output:

The calendar time expressed as a local Time is :
UTC:   Thu Aug 03 11:15:59 2017
local: Thu Aug 03 16:45:59 2017

N.B.: The result may varry for your current system date and time.

Flowchart:

C Programming Code Editor:

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