C语言时间函数之mktime和difftime详解

	__CRT_INLINE time_t __cdecl mktime(struct tm *_Tm);
	__CRT_INLINE double __cdecl difftime(time_t _Time1,time_t _Time2);

struct tm {
   int tm_sec;         
   int tm_min;         
   int tm_hour;        
   int tm_mday;        
   int tm_mon;         
   int tm_year;        
   int tm_wday;        
   int tm_yday;        
   int tm_isdst;           
};

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main(int arGC, char** argv)
{
    int ret,time_cnt;
    struct tm info;
    info.tm_year = 2022 - 1900;
    info.tm_mon = 1 - 1;
    info.tm_mday = 25;
    info.tm_hour = 11;
    info.tm_min = 28;
    info.tm_sec = 50;
    info.tm_isdst = -1;
    ret = mktime(&info);
    time_cnt = time(NULL);
    if( ret == -1 ) {
        printf("Error: unable to make time using mktime\n");
    } else {
        printf("%d %d",ret,time_cnt);
    }
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main(int argc, char** argv)
{
	time_t start_t, end_t;
	double diff_t;
	printf("程序启动...\n");
	time(&start_t);
	sleep(2);
	printf("运行结束！\n");
	time(&end_t);
	diff_t = difftime(end_t, start_t);
	printf("\n开始时间: %d 结束时间: %d 代码运行时间: %fs\n", start_t,end_t,diff_t);
	return 0;
}