1. 1. Time.h
      1. Time_t

Time_t 它本身是一个long 类型

Time(time_t *time_t) 是给一个time_t变量赋值为当前数据

Time_t now;

Time(&now);

1. 1. 1. Struct tm

这个tm结构体，里面放了year month  day  hour minute second

struct tm

{

  int tm_sec; /* Seconds. [0-60] (1 leap second) */

  int tm_min; /* Minutes. [0-59] */

  int tm_hour; /* Hours. [0-23] */

  int tm_mday; /* Day. [1-31] */

  int tm_mon; /* Month. [0-11] */

  int tm_year; /* Year - 1900.  */

  int tm_wday; /* Day of week. [0-6] */

  int tm_yday; /* Days in year.[0-365] */

  int tm_isdst; /* DST. [-1/0/1]*/

}

1. 1. 1. Localtime

extern struct tm *localtime (const time_t *__timer) __THROW;

localtime可以把time_t(long)转换成一个结构体

Struct tm *t = localtime(&now);

Localtime(&now)转换的当前时间给tm  year = 真实year-1900

Month = 真实month -1

1. 1. 1. Mktime

  extern time_t mktime (struct tm *__tp) __THROW;

Mktime把结构体 tm转换成 time_t

time_t convertToTime_t(int year,int month,int day,int hour,int minute,int seconds){

    struct tm info = {0};

    info.tm_year = year-1900;（需要-1900）

    info.tm_mon = month-1; （需要月份-1）

    info.tm_mday = day;

    info.tm_hour = hour;

    info.tm_min = minute;

    info.tm_sec = seconds;

    time_t t=  mktime(&info);

    return t;

}

1. 1. 1. Gmtime

/* Return the `struct tm' representation of *TIMER

   in Universal Coordinated Time (aka Greenwich Mean Time).  */

extern struct tm *gmtime (const time_t *__timer) __THROW;

这个与localtime()区别就是它获取的时间hour需要-8

1. 1. 1. Ctime  asctime()

都是返回字符串

#include
#include
#include
#include
#include
#include
#include
#include
#include        /* sqrt */

void time_to_long();
char *formate_current_date();
int diffday(time_t t1,time_t t2);

void time_to_long(){
    
    time_t timep;
    struct tm *p;
    time(&timep);
    p = gmtime(&timep);

    long longsec = 1000;
    long longmin = 60 *1000;
    long longhour = 60 * 60 * 1000;
    long day = 24 * 60 * 60 * 1000;
    // long month =  

    // long ss = p->tm_sec * 1000+ p->tm_min*60*1000 + (8+p->tm_hour)*60*60*1000;
    
    printf("aaa\n");
}

char *formate_current_date(){

    time_t timep;
    struct tm *p;
    struct tm *info;
    // char time1[28];
    char * time1 = (char *)calloc(28,sizeof(char *));
    time(&timep);
    info = localtime(&timep);
    p = gmtime(&timep);
    
    /**年需要+1900  月需要+1   小时需要+8 注意日期需要选m_day*/
    /**这个time1使用的是calloc，需要在调用的地方free(time1),释放内存*/
    sprintf(time1,"%d-%d-%d %d:%d:%d",1900+p->tm_year,1+p->tm_mon,p->tm_mday,8+p->tm_hour,p->tm_min,p->tm_sec);
    printf("time1 %s\n",time1);

    return time1;
}

// void getCurretTime(){

//     struct timeval tv;

//     gettimeofday(&tv,NULL);

//     int aa = tv.tv_sec * 1000 + tv.tv_usec / 1000;
//     printf("getCurretTime: %d\n",aa);
//     return tv.tv_sec * 1000 + tv.tv_usec / 1000;

// }

long getCurrentTime2(){
    time_t now;
    time(&now);
    printf("now:%ld\n",now);
    printf("now:%ld\n",now);
    long ss = now;
    // 1673244657   1673244537
    long sa = (ss*1000) -(1673244537 * 1000);
    printf("ssss:%ld \n",ss);
    printf("ssssaaaaa:%ld \n",sa);
    return sa;
}

char * getName(){
    char * name = "myname is name";
    return name;
}

char *getName2(){
    char name[] = "fefefe";
    return name;
}

time_t convertToTime_t(int year,int month,int day,int hour,int minute,int seconds){

    time_t now;
    time(&now);
    // struct tm *info = {0};
    // info->tm_year = year-1900;
    // info->tm_mon = month-1;
    // info->tm_mday = day;
    // info->tm_hour = hour-8;
    // info->tm_min = minute;
    // info->tm_sec = seconds;
    // time_t t=  mktime(info);

    struct tm info = {0};
    info.tm_year = year-1900;
    info.tm_mon = month-1;
    info.tm_mday = day;
    info.tm_hour = hour;
    info.tm_min = minute;
    info.tm_sec = seconds;
    time_t t=  mktime(&info);
    return t;
}

void testlocaltime(){

    // time_t now;
    // time(&now);
    // time_t now2;
    // struct tm * tm2 = localtime(&now2);
    // struct tm * tm = localtime(&now);
    // printf("aaaa %s \n",asctime(tm))  ;
    // printf("bbbbb %s \n",asctime(tm2))  ;
    // printf("aaa\n");

    
    // double aa = difftime(convertToTime_t(1999,10,10,0,0,0),convertToTime_t(1980,3,3,0,0,0));
    // printf("aaaadfdfdf:%d\n",aa);

    // int diff = diffday(convertToTime_t(1999,10,10,0,0,0),convertToTime_t(1980,3,3,0,0,0));
    // printf("bbbb diff %d\n",diff);

    // time_t now;
    // struct tm *tm = localtime(&now);
    // printf("asctime(tm) :%s \n",asctime(tm));  //这个样子不对，需要给now赋值才行

    time_t now;
    time(&now);//赋值当前时间
    struct tm *t = localtime(&now);
    printf("asctime(tm) :%s \n",asctime(t));

    time_t p = convertToTime_t(1998,10,10,13,14,15);
    struct tm *info = localtime(&p);
    printf("pppp: %ld\n",p);
    printf("asctime(info) :%s \n",asctime(info));

    time_t now2;
    time(&now2);
    printf("citme sss %s\n",ctime(&now2));

}

int diffday(time_t t1,time_t t2){
    int diff = (int)(t1-t2);
    return diff/(24*3600);
}

// int frequency_of_primes (int n) {
//   int i,j;
//   int freq=n-1;
//   for (i=2; i<=n; ++i) for (j=sqrt(i);j>1;--j) if (i%j==0) {--freq; break;}
//   return freq;
// }

void testclock(){
    clock_t t;
    int f;
    t = clock();
    printf ("Calculating...\n");
    // f = frequency_of_primes(99999);
    // printf ("The number of primes lower than 100,000 is: %d\n",f);
    t = clock()-t;
    // printf ("It took me %d clicks (%f seconds).\n",t,((float)t)/CLOCKS_PER_SEC);
}

int main(){

    // https://blog.csdn.net/xuehuafeiwu123/article/details/77944893
    // https://blog.csdn.net/weixin_29938067/article/details/117118688
    printf("test2222222\n");
    time_to_long();
    formate_current_date();
    // getCurretTime();
    long sese =  getCurrentTime2();
    long sesqq = 10;
    printf("sesqq :%ld\n",sesqq);
    printf("sese :%d\n",sese);
    char *myname = getName();
    printf("myname %s\n",myname);

    char *name2222 = getName2();
    printf("name222 %s\n",name2222);
    time_t t = convertToTime_t(1980,3,10,15,13,22);
    printf("time_ttime_t %d\n",t);
    testlocaltime();
    testclock();
    // frequency_of_primes(99999);
    return 0;
}