C++学习笔记3----时间与时间戳

自 1970 年 1 月 1 日以来经过的秒数:
time_t time1 = time(0);//这里获取到的其实就是一个long类型的时间戳，是秒级别的，非毫秒级别

    time_t time1 = time(0);
    cout << "time1 = " << time1 << endl;//1498122787
    char * strTime = ctime(&time1);
    cout << "strTime = " << strTime << endl;//Thu Jun 22 17:13:07 2017

    time_t startTime = 1498122787;
    double betweenSecond = difftime(time1, startTime);//该函数返回 time1 和 time2 之间相差的秒数。
    cout << "betweenSecond = " << betweenSecond << endl;//Thu Jun 22 17:13:07 2017

1.时间戳转格式化

time_t t = time(0);
struct tm *p;
p=gmtime(&t);
char s[100];
strftime(s, sizeof(s), "%Y-%m-%d %H:%M:%S", p);
printf("%d: %s\n", (long)t, s); //1498124250: 2017-06-22 09:37:30

2.格式化转时间戳

long getTick(char *str_time)
{
    struct tm stm;
    int iY, iM, iD, iH, iMin, iS;

    memset(&stm,0,sizeof(stm));

    iY = atoi(str_time);
    iM = atoi(str_time+5);
    iD = atoi(str_time+8);
    iH = atoi(str_time+11);
    iMin = atoi(str_time+14);
    iS = atoi(str_time+17);

    stm.tm_year=iY-1900;
    stm.tm_mon=iM-1;
    stm.tm_mday=iD;
    stm.tm_hour=iH;
    stm.tm_min=iMin;
    stm.tm_sec=iS;
    return mktime(&stm);
}

int main()  
{  
    char str_time[19];  
    printf("请输入时间:"); /*(格式:2011-12-31 11:43:07)*/  
    gets(str_time);  
    printf("%ld\n", GetTick(str_time));  
    return 0;      
}