C/Development/Time Date
Содержание
- 1 converts earth days into Jovian years
- 2 Convert time_t value to string: how to use ctime
- 3 Convert time_t value to tm structure as UTC time: how to use gmtime
- 4 Convert time_t value to tm structure in local time: How to use localtime
- 5 Convert tm structure to string: how to use asctime
- 6 Convert tm structure to time_t value: how to use mktime
- 7 Create local time from time()
- 8 Display a date
- 9 Get current time: how to use time and time_t
- 10 Get the elapsed time: clock and CLOCKS_PER_SEC
- 11 Get time: how to use time() and time_t
- 12 Get time: now
- 13 Getting date data with ease
- 14 Getting the time as a string
- 15 How to check the performance: difftime
- 16 How to get local time: localtime and asctime
- 17 Local time and Coordinated Universal Time and date
- 18 Make time: hour, minute, second, year, day, month
- 19 Print local and UTC time
- 20 Return difference between two times: how to use difftime
- 21 Return number of clock ticks since process start
converts earth days into Jovian years
#include <stdio.h>
int main(void)
{
float earth_days; /* number of earth days */
float jovian_years; /* equivalent number of Jovian years */
printf("Enter number of earth days: ");
scanf("%f", &earth_days);
jovian_years = earth_days / (365.0 * 12.0);
printf("Equivalent Jovian years: %f", jovian_years);
return 0;
}
Convert time_t value to string: how to use ctime
#include <stdio.h>
#include <time.h>
int main () {
time_t rawtime;
time ( &rawtime );
printf ( "Current date and time are: %s", ctime (&rawtime) );
return 0;
}
Convert time_t value to tm structure as UTC time: how to use gmtime
#include <stdio.h>
#include <time.h>
#define PST (-8)
#define CET (1)
#define BJ (8)
int main ()
{
time_t rawtime;
struct tm *p;
time ( &rawtime );
p = gmtime ( &rawtime );
printf ("Time in Los Angeles: %2d:%02d\n", p->tm_hour+PST, p->tm_min);
printf ("Time in Berlin: %2d:%02d\n", p->tm_hour+CET, p->tm_min);
printf ("Time in Bei Jing: %2d:%02d\n", p->tm_hour+BJ, p->tm_min);
return 0;
}
Convert time_t value to tm structure in local time: How to use localtime
#include <stdio.h>
#include <time.h>
int main ()
{
time_t rawtime;
struct tm *tminfo;
time ( &rawtime );
tminfo = localtime ( &rawtime );
printf ( "Current date and time are: %s", asctime (tminfo) );
return 0;
}
Convert tm structure to string: how to use asctime
#include <stdio.h>
#include <time.h>
int main ()
{
time_t rawtime;
struct tm *timeinfo;
time ( &rawtime );
timeinfo = localtime ( &rawtime );
printf ( "Current date and time are: %s", asctime (timeinfo) );
return 0;
}
Convert tm structure to time_t value: how to use mktime
#include <stdio.h>
#include <time.h>
int main ()
{
time_t rawtime;
struct tm *timeinfo;
int year = 2005, month = 2 ,day = 2;
char * weekday[] = { "Sunday", "Monday",
"Tuesday", "Wednesday",
"Thursday", "Friday", "Saturday"};
/* get current timeinfo and modify it to user"s choice */
time ( &rawtime );
timeinfo = localtime ( &rawtime );
timeinfo->tm_year = year - 1900;
timeinfo->tm_mon = month - 1;
timeinfo->tm_mday = day;
/* call mktime: timeinfo->tm_wday will be set */
mktime ( timeinfo );
printf ("That day is a %s.\n", weekday[timeinfo->tm_wday]);
return 0;
}
Create local time from time()
#include <time.h>
#include <stdio.h>
int main(void)
{
struct tm *ptr;
time_t lt;
char str[80];
lt = time(NULL);
ptr = localtime(<);
strftime(str, 100, "It is now %H %p.", ptr);
printf(str);
return 0;
}
Display a date
#include <stdio.h>
void main()
{
int month = 0;
int day = 0;
int year = 0;
printf("Enter the date as three integer values separated by spaces (month day year):\n");
scanf("%d", &month);
scanf("%d", &day);
scanf("%d", &year);
if(day>3 && day<21 || day>23 && day<31)
printf("\n%dth ",day);
else
printf("\n%d%s ", day, (day%10 == 1 ? "st": (day%10 == 2 ? "nd" : "rd")));
switch(month)
{
case 1:
printf("January ");
break;
case 2:
printf("February ");
break;
case 3:
printf("March ");
break;
case 4:
printf("April ");
break;
case 5:
printf("May");
break;
case 6:
printf("June");
break;
case 7:
printf("July");
break;
case 8:
printf("August");
break;
case 9:
printf("September");
break;
case 10:
printf("October");
break;
case 11:
printf("November");
break;
case 12:
printf("December");
break;
}
printf(" %d\n", year);
}
Get current time: how to use time and time_t
#include <stdio.h>
#include <time.h>
int main ()
{
time_t seconds;
seconds = time (NULL);
printf ("%ld hours since January 1, 1970", seconds/3600);
return 0;
}
Get the elapsed time: clock and CLOCKS_PER_SEC
#include <time.h>
#include <stdio.h>
int main(void)
{
printf("Elapsed time: %u secs.\n", clock()/CLOCKS_PER_SEC);
return 0;
}
Get time: how to use time() and time_t
#include <time.h>
#include <stdio.h>
int main(void)
{
time_t lt;
lt = time(NULL);
printf(ctime(<));
return 0;
}
Get time: now
#include <stdio.h> /* For input and output */
#include <time.h> /* For time() and clock() functions */
void main() {
long time_taken = clock();
printf("%ld\n", time_taken);
printf("%d\n", CLOCKS_PER_SEC);
}
Getting date data with ease
#include <stdio.h>
#include <time.h>
void main()
{
char *Day[7] = {
"Sunday" , "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday", "Saturday"
};
char *Month[12] = {
"January", "February", "March", "April",
"May", "June", "July", "August",
"September", "October", "November", "December"
};
char *Suffix[] = { "st", "nd", "rd", "th" };
int i = 3;
struct tm *OurT = NULL;
time_t Tval = 0;
Tval = time(NULL);
OurT = localtime(&Tval);
switch( OurT->tm_mday )
{
case 1: case 21: case 31:
i= 0; /* Select "st" */
break;
case 2: case 22:
i = 1; /* Select "nd" */
break;
case 3: case 23:
i = 2; /* Select "rd" */
break;
default:
i = 3; /* Select "th" */
break;
}
printf("\nToday is %s the %d%s %s %d", Day[OurT->tm_wday],
OurT->tm_mday, Suffix[i], Month[OurT->tm_mon], 1900 + OurT->tm_year);
printf("\nThe time is %d : %d : %d",
OurT->tm_hour, OurT->tm_min, OurT->tm_sec );
}
Getting the time as a string
#include <stdio.h>
#include <time.h>
#include <string.h>
#define TIME_24 1
#define TIME_12 0
char *get_time_string(int mode24); /* Returns the time as a string in 12 or 24 hour format */
int main()
{
char time_str[12];
get_time_string(TIME_24);
printf("\n\n");
get_time_string(TIME_12);
}
char* get_time_string(int mode24)
{
static char time_str[12] = {0}; /* Stroes the time as a string */
struct tm *now = NULL;
int hour = 0;
time_t time_value = 0;
time_value = time(NULL); /* Get time value */
now = localtime(&time_value); /* Get time and date structure */
hour = now->tm_hour; /* Save the hour value */
if(!mode24 && hour>12) /* Adjust if 12 hour format */
hour -= 12;
printf("%d:",hour);
printf("%d:",now->tm_min);
printf("%d",now->tm_sec);
if(!mode24)
if(now->tm_hour>24){
printf("PM\n");
}else{
printf("AM\n");
}
return time_str;
}
How to check the performance: difftime
#include <time.h>
#include <stdio.h>
int main(void)
{
time_t start,end;
volatile long unsigned t;
start = time(NULL);
for(t = 0; t < 5000000; t++)
;
end = time(NULL);
printf("Loop used %f seconds.\n", difftime(end, start));
return 0;
}
How to get local time: localtime and asctime
#include <time.h>
#include <stdio.h>
int main(void)
{
struct tm *ptr;
time_t lt;
lt = time(NULL);
ptr = localtime(<);
printf(asctime(ptr));
return 0;
}
Local time and Coordinated Universal Time and date
#include <time.h>
#include <stdio.h>
/* Print local and UTC time. */
int main(void)
{
struct tm *local, *gm;
time_t t;
t = time(NULL);
local = localtime(&t);
printf("Local time and date: %s\n", asctime(local));
gm = gmtime(&t);
printf("Coordinated Universal Time and date: %s", asctime(gm));
return 0;
}
Make time: hour, minute, second, year, day, month
#include <time.h>
#include <stdio.h>
int main(void)
{
struct tm t;
time_t t_of_day;
t.tm_year = 2005-1900;
t.tm_mon = 0;
t.tm_mday = 3;
t.tm_hour = 0; /* hour, min, sec don"t matter */
t.tm_min = 0; /* as long as they don"t cause a */
t.tm_sec = 1; /* new day to occur */
t.tm_isdst = 0;
t_of_day = mktime(&t);
printf(ctime(&t_of_day));
return 0;
}
Print local and UTC time
#include <time.h>
#include <stdio.h>
int main(void)
{
struct tm *local;
time_t t;
t = time(NULL);
local = localtime(&t);
printf("Local time and date: %s\n", asctime(local));
local = gmtime(&t);
printf("UTC time and date: %s\n", asctime(local));
return 0;
}
Return difference between two times: how to use difftime
#include <stdio.h>
#include <time.h>
int main ()
{
time_t start, end;
char str[256];
double dif;
time (&start);
printf ("Please, enter your name: ");
gets (str);
time (&end);
dif = difftime (end, start);
printf ("You have taken %.2lf seconds to type your name.\n", dif );
return 0;
}
Return number of clock ticks since process start
#include <stdio.h>
#include <time.h>
void wait ( int seconds ) {
clock_t endwait;
endwait = clock () + seconds * CLK_TCK ;
while (clock() < endwait) {
}
}
int main ()
{
int i;
printf ("Starting count down...\n");
for (i = 20; i > 0; i--) {
printf (" i = %d\n",i);
wait (1);
}
printf ("Done!!!\n");
return 0;
}