C Exercises: Convert a time_t object to calendar time expressed as Coordinated Universal Time

Last update on May 27 2022 12:20:20 (UTC/GMT +8 hours)

C Date Time: Exercise-6 with Solution

Write a program in C to convert a time_t object to calendar time expressed as Coordinated Universal Time.

Sample Solution:

C Code:

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

int main(void)
{
    time_t t = time(NULL);
    printf("\nThe calendar time expressed as Coordinated Universal Time is :");
    printf("\nUTC:   %s", asctime(gmtime(&t)));
    printf("local: %s\n", asctime(localtime(&t)));
 
#ifdef __STDC_LIB_EXT1__
    struct tm buf;
    char str[26];
    asctime_s(str,sizeof str,gmtime_s(&t, &buf));
    printf("UTC:   %s", str);
    asctime_s(str,sizeof str,localtime_s(&t, &buf)));
    printf("local: %s", str);
#endif
}

Sample Output:

The calendar time expressed as Coordinated Universal Time is :
UTC:   Thu Aug 03 10:53:03 2017
local: Thu Aug 03 16:23:03 2017

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

Flowchart:

C Programming Code Editor:

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C Programming: Tips of the Day

Static variable inside of a function in C

The scope of variable is where the variable name can be seen. Here, x is visible only inside function foo().

The lifetime of a variable is the period over which it exists. If x were defined without the keyword static, the lifetime would be from the entry into foo() to the return from foo(); so it would be re-initialized to 5 on every call.

The keyword static acts to extend the lifetime of a variable to the lifetime of the programme; e.g. initialization occurs once and once only and then the variable retains its value - whatever it has come to be - over all future calls to foo().

Ref : https://bit.ly/3fOq7XP