c语言头文件time.h

#include <stdio.h>#include <time.h>void main(){time_t sec;       //typedef long time_tstruct tm * curTime;sec = time(NULL);           //获取时间，从1970.1.1到现在的秒数,也可以写成 time(&sec);curTime = localtime(&sec);  //把sec转换为当地时间，存于时间结构体curTime中，注意返回值是struct tm* 类型的printf("asctime(curTime): %s\n", asctime (curTime));        //asctime(struct tm*)函数将curTime转化成标准ASCII时间格式printf("ctime(curTime):   %s\n", ctime (&sec));        //ctime(time_t*)直接将sec转换成标准时间格式printf("%d-%d-%d %d:%d:%d\n", 1900+curTime->tm_year, 1+curTime->tm_mon,curTime->tm_mday, curTime->tm_hour, curTime->tm_min, curTime->tm_sec);//手动输出struct tm中的字段，其中月份加1，年份要加1900，//sec记录的是1970到现在的秒数，为什么是加1900呢？？？printf("\nsec = %ld\nmktime(curTime) = %ld\n", sec, mktime(curTime));//time_t mktime(struct tm*)将curTime反向转化成1970到现在的秒数}