我在做redis定時任務的時候需要檢測部分資料的過期時間，為了方便管理，獲取到的時間需要轉換成我們平常看到的字串格式，在網上看了一些朋友的實現方式結合自身的使用進行了一些修改。

#include <time.h>
#include <string>

//轉換成 "2017-07-20 17:44:06"
int Time_tToString(std::string &strDateStr, const time_t &timeDate)
{
	char temp[100];
	memset(temp, 0, sizeof(temp));
	struct tm *p;
	p = localtime(&timeDate);
	
	p->tm_year = p->tm_year + 1900;
	p->tm_mon = p->tm_mon + 1;
	
	_snprintf(temp, sizeof(temp), "%04d-%02d-%02d %02d:%02d:%-2d", p->tm_year, p->tm_mon, p->tm_mday, p->tm_hour, p->tm_min, p->tm_sec);
	strDateStr = temp;
	
	return 0;
}

int StringToTime_t(cosnt std::string &strDateStr, time_t &time)
{
	char *pBeginPos = (char *)strDateeStr.c_str();
	char *pPos = strstr(pBeginPos,"-");
	if(pPos == NULL)
		return -1;
	
	int iYear = atoi(pBeginPos);
	int iMonth = atoi(pPos + 1);
	pPos = strstr(pPos + 1, "-");
	if(pPos == NULL)
		return -1;
	
	int iDay = atoi(pPos + 1);
	int iHour = 0;
	int iMin = 0;
	int iSec = 0;
	pPos = strstr(pPos + 1, " ");
	if(pPos != NULL)
	{
		iHour = atoi(pPos + 1);
		pPos = strstr(pPos + 1, ":");
		if(pPos != NULL)
		{
			iMin = atoi(pPos + 1);
			pPos = strstr(pPos + 1, ":");
			if(pPos != NULL)
			{
				iSec = atoi(pPos + 1);
			}
		}
	}
	
	struct tm sourcedate;
	memset((void*)&sourcedate, 0, sizeof(sourcedate));
	sourcedate.tm_sec = iSec;
	sourcedate.tm_min = iMin;
	sourcedate.tm_hour = iHour;
	sourcedate.tm_mday = iDay;
	sourcedate.tm_mon = iMonth -1;
	sourcedate.tm_year = iYear - 1900;
	time = mktime(&sourcedate);
	return 0;
}

int main()

{
	string timeStr;
	time_t time, oldTime, nowTime;
	time(&time);
	Time_tToString(timeStr, time);
	Sleep(3000);
	StringToTime_t(timeStr, oldTime);
	if (diff(nowTime, oldTime) > 2)
		cout << "~~~~" << endl;
	getchar();
	
	return 0;
}