c - 在 C 中获取当前时间

Question

我想获取系统的当前时间。为此，我在 C 中使用以下代码：

time_t now;
struct tm *mytime = localtime(&now); 
if ( strftime(buffer, sizeof buffer, "%X", mytime) )
{
    printf("time1 = \"%s\"\n", buffer);
}

问题是这段代码给出了一些随机时间。而且，随机时间每次都不一样。我想要我的系统的当前时间。

Answer 1

从这里复制粘贴：

/* localtime example */
#include <stdio.h>
#include <time.h>

int main ()
{
  time_t rawtime;
  struct tm * timeinfo;

  time ( &rawtime );
  timeinfo = localtime ( &rawtime );
  printf ( "Current local time and date: %s", asctime (timeinfo) );
  
  return 0;
}

（只需添加void到main()参数列表中，以便在 C 中工作）

Answer 2

初始化你的now变量。

time_t now = time(0); // Get the system time

该localtime函数用于将传递的时间值转换time_t为 a struct tm，它实际上并不检索系统时间。

Answer 3

简单的方法：

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

int main(void)
{
    time_t mytime = time(NULL);
    char * time_str = ctime(&mytime);
    time_str[strlen(time_str)-1] = '\0';
    printf("Current Time : %s\n", time_str);

    return 0;
}

Answer 4

为了扩展上面@mingos 的答案，我编写了以下函数来将我的时间格式化为特定格式（[dd mm yyyy hh:mm:ss]）。

// Store the formatted string of time in the output
void format_time(char *output){
    time_t rawtime;
    struct tm * timeinfo;
    
    time(&rawtime);
    timeinfo = localtime(&rawtime);
    
    sprintf(output, "[%d %d %d %d:%d:%d]", timeinfo->tm_mday,
            timeinfo->tm_mon + 1, timeinfo->tm_year + 1900,
            timeinfo->tm_hour, timeinfo->tm_min, timeinfo->tm_sec);
}

更多信息struct tm可以在这里找到。

Answer 5

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

void main()
{
    time_t t;
    time(&t);
    printf("\n current time is : %s",ctime(&t));
}

Answer 6

您可以使用此功能获取当前本地时间。如果你想要 gmt 然后使用gmtime函数而不是localtime. 干杯

time_t my_time;
struct tm * timeinfo; 
time (&my_time);
timeinfo = localtime (&my_time);
CCLog("year->%d",timeinfo->tm_year+1900);
CCLog("month->%d",timeinfo->tm_mon+1);
CCLog("date->%d",timeinfo->tm_mday);
CCLog("hour->%d",timeinfo->tm_hour);
CCLog("minutes->%d",timeinfo->tm_min);
CCLog("seconds->%d",timeinfo->tm_sec);

Answer 7

如果您只需要没有日期的时间。

  time_t rawtime;
  struct tm * timeinfo;
  time( &rawtime );
  timeinfo = localtime( &rawtime );
  printf("%02d:%02d:%02d", timeinfo->tm_hour, timeinfo->tm_min, 
    timeinfo->tm_sec);

Answer 8

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

void main()
{
    time_t t;
    time(&t);
    clrscr();

    printf("Today's date and time : %s",ctime(&t));
    getch();
}

Answer 9

建议使用localtime_s而不是localtime. 这应该有效。

time_t current_raw_time = time(0); // System time: number of seconds since 00:00, Jan 1 1970 UTC
struct tm day_time;
localtime_s(&day_time, &current_raw_time);

day_time将有以下成员：

struct tm
{
    int tm_sec;   // seconds after the minute - [0, 60] including leap second
    int tm_min;   // minutes after the hour - [0, 59]
    int tm_hour;  // hours since midnight - [0, 23]
    int tm_mday;  // day of the month - [1, 31]
    int tm_mon;   // months since January - [0, 11]
    int tm_year;  // years since 1900
    int tm_wday;  // days since Sunday - [0, 6]
    int tm_yday;  // days since January 1 - [0, 365]
    int tm_isdst; // daylight savings time flag
};

请注意，localtime不提供毫秒。

Answer 10

长版

来源：https ://en.wikipedia.org/wiki/C_date_and_time_functions

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

int main(void)
{
    time_t current_time;
    char* c_time_string;

    /* Obtain current time. */
    current_time = time(NULL);

    if (current_time == ((time_t)-1))
    {
        (void) fprintf(stderr, "Failure to obtain the current time.\n");
        exit(EXIT_FAILURE);
    }

    /* Convert to local time format. */
    c_time_string = ctime(&current_time);

    if (c_time_string == NULL)
    {
        (void) fprintf(stderr, "Failure to convert the current time.\n");
        exit(EXIT_FAILURE);
    }

    /* Print to stdout. ctime() has already added a terminating newline character. */
    (void) printf("Current time is %s", c_time_string);
    exit(EXIT_SUCCESS);
}

输出是：

Current time is Thu Sep 15 21:18:23 2016

精简版：

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

int main(int argc, char *argv[]) {
    time_t current_time;
    time(&current_time);
    printf("%s", ctime(&current_time));

输出是：

Current time is Thu Jan 28 15:22:31 2021

Answer 11

伙计们，我有一种获取系统时间的新方法。虽然它很长并且充满了愚蠢的作品，但通过这种方式，您可以获得整数格式的系统时间。

#include <stdio.h>
#include <stdlib.h>

int main()
{
    FILE *fp;
    char hc1,hc2,mc1,mc2;
    int hi1,hi2,mi1,mi2,hour,minute;
    system("echo %time% >time.txt");
    fp=fopen("time.txt","r");
    if(fp==NULL)
       exit(1) ;
    hc1=fgetc(fp);
    hc2=fgetc(fp);
    fgetc(fp);
    mc1=fgetc(fp);
    mc2=fgetc(fp);
    fclose(fp);
    remove("time.txt");
    hi1=hc1;
    hi2=hc2;
    mi1=mc1;
    mi2=mc2;
    hi1-=48;
    hi2-=48;
    mi1-=48;
    mi2-=48;
    hour=hi1*10+hi2;
    minute=mi1*10+mi2;
    printf("Current time is %d:%d\n",hour,minute);
    return 0;
}