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Time functions in C are used to interact with system time routine and formatted time outputs are displayed. Example programs for the time functions are given below.
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S.no |
Function
|
Description
|
1 | setdate() | This function used to modify the system date |
2 | getdate() | This function is used to get the CPU time |
3 | clock() | This function is used to get current system time |
4 | time() | This function is used to get current system time as structure |
5 | difftime() | This function is used to get the difference between two given times |
6 | strftime() | This function is used to modify the actual time format |
7 | mktime() | This function interprets tm structure as calendar time |
8 | localtime() | This function shares the tm structure that contains date and time informations |
9 | gmtime() | This function shares the tm structure that contains date and time informations |
10 | ctime() | This function is used to return string that contains date and time informations |
11 | asctime() | Tm structure contents are interpreted by this function as calendar time. This time is converted into string. |
Example program for setdate() function in C:
This function is used to modify the system date.
#include<stdio.h> #include<dos.h> #include<conio.h> int main() { struct date dt; printf("Enter new date in the format(day month year)"); scanf("%d%d%d",&dt.da_day,&dt.da_mon,&dt.da_year); setdate(&dt); printf("Now, current system date is %d-%d-%dn" ,dt.da_day,dt.da_mon,dt.da_year); return 0; }
Output:
Enter new date in the format(day month year) 01 12 2012 Now, current system date is 01-12-2012 |
Example program for getdate() function in C:
This function is used to get the CPU time.
#include<stdio.h> #include<dos.h> int main() { struct date dt; getdate(&dt); printf("Operating system's current date is %d-%d-%dn" ,dt.da_day,dt.da_mon,dt.da_year); return 0; }
Output:
Operating system’s current date is 12-01-2012 |
Example program for clock() function in C:
This function is used to get current system time
#include <stdio.h> #include <time.h> #include <math.h> int main() { int i; clock_t CPU_time_1 = clock(); printf("CPU start time is : %d n", CPU_time_1); for(i = 0; i < 150000000; i++); clock_t CPU_time_2 = clock(); printf("CPU end time is : %d", CPU_time_2); }
Output:
CPU start time is : 0
CPU end time is : 380000 |
Example program for time() function in C:
This function is used to get current system time as structure
#include <stdio.h> #include <time.h> int main () { time_t seconds; seconds = time (NULL); printf ("Number of hours since 1970 Jan 1st " "is %ld n", seconds/3600); return 0; }
Output:
Number of hours since 1970 Jan 1st is 374528 |
Example program for difftime() function in C:
This function is used to get the difference between two given times
#include <stdio.h> #include <time.h> int main() { time_t begin,end; long i; begin= time(NULL); for(i = 0; i < 150000000; i++); end = time(NULL); printf("for loop used %f seconds to complete the " "executionn", difftime(end, begin)); return 0; }
Output:
for loop used 15.000000 seconds to complete the execution |
Example program for strftime(), asctime() and localtime() in C:
- strftime() – This function is used to modify the actual time format.
- asctime() – tm structure contents are interpreted by asctime() function as calendar time. This time is converted into string.
- localtime() – This function shares the tm structure that contains date and time informations.
#include <stdio.h> #include <time.h> #define LEN 150 int main () { char buf[LEN]; time_t curtime; struct tm *loc_time; //Getting current time of system curtime = time (NULL); // Converting current time to local time loc_time = localtime (&curtime); // Displaying date and time in standard format printf("%s", asctime (loc_time)); strftime (buf, LEN, "Today is %A, %b %d.n", loc_time); fputs (buf, stdout); strftime (buf, LEN, "Time is %I:%M %p.n", loc_time); fputs (buf, stdout); return 0; }
Output:
Sat Sep 22 01:15:03 2012 Today is Saturday, Sep 22. Time is 01:15 AM. |
Example program for mktime() and ctime() functions in C:
- mktime() function interprets tm structure as calendar time.
- ctime() function is used to return string that contains date and time informations.
#include <stdio.h> #include <time.h> int main() { struct tm strtime; time_t timeoftheday; strtime.tm_year = 2008-1900; strtime.tm_mon = 1; strtime.tm_mday = 4; strtime.tm_hour = 02; strtime.tm_min = 30; strtime.tm_sec = 38; strtime.tm_isdst = 0; timeoftheday = mktime(&strtime); printf(ctime(&timeoftheday)); return 0; }
Output:
Mon Feb 4 02:30:38 2008 |
Example program for gmtime() function in C:
This function shares the tm structure that contains date and time informations.
#include <stdio.h> #include <time.h> int main() { time_t orig_format; time(&orig_format); printf ("Universal Time is %s", asctime(gmtime(&orig_format))); return 0; }
Output:
Universal Time is Sat Sep 22 08:11:40 2012 |
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