mktime函数实现获取当前系统时间

#include<stdio.h>
#include<time.h>

char displayTime[14];

int main( )
{
time_t timep;
struct tm *p;

while(1){
time(&timep);
//printf("\rtime():%ld\n",timep); //打印从1900年到当前的时间的秒数，每一次打印出的时间都不同

p = localtime(&timep);
timep = mktime(p);

/************************************以下内容的方法可用在写RTC驱动在LCD上显示*******************************************/

displayTime[0] = 0x30+ (p->tm_year + 1900) / 1000; //年 0x30 = '0'
displayTime[1] = 0x30+ (p->tm_year + 1900) % 1000 / 100;
displayTime[2] = 0x30+ (p->tm_year + 1900) % 100 / 10;
displayTime[3] = 0x30+(p->tm_year + 1900) % 10;

displayTime[4] = 0x30+ (p->tm_mon + 1) / 10; //月
displayTime[5] = 0x30+(p->tm_mon + 1) % 10;

displayTime[6] = 0x30+p->tm_mday / 10; //日
displayTime[7] = 0x30+p->tm_mday % 10;

displayTime[8] = 0x30+p->tm_hour / 10; //时
displayTime[9] = 0x30+p->tm_hour % 10;

displayTime[10] = 0x30+ p->tm_min / 10; //分
displayTime[11] = 0x30+p->tm_min % 10;

displayTime[12] = 0x30+p->tm_sec / 10; //秒
displayTime[13] = 0x30+p->tm_sec % 10;

printf("\r%d%d%d%d-%d%d-%d%d %d%d:%d%d:%d%d",displayTime[0],displayTime[1],displayTime[2],\
displayTime[3],displayTime[4],displayTime[5],\
displayTime[6],displayTime[7],displayTime[8],\
displayTime[9],displayTime[10],displayTime[11],\
displayTime[12],displayTime[13]);
/**************************************************以下内容的方法可在写RTC驱动控制台和串口上显示***********************************/
//printf("\r%4d-%02d-%02d %02d:%02d:%02d",p->tm_year+1900,p->tm_mon+1,p->tm_mday,p->tm_hour,p->tm_min,p->tm_sec);
}
}