利用函式庫獲取當前時間。

1、

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

int main(void)
{
    time_t current = time(NULL);
    struct tm *timer = localtime(&current);
    
    printf("current date and time:\n%d-%d-%d; week: %d; %d-%d-%d\n",
    timer -> tm_year + 1900,
    timer -> tm_mon + 1,
    timer 
 
-> tm_mday,
    timer -> tm_wday,
    timer -> tm_hour,
    timer -> tm_min,
    timer -> tm_sec);
    return 0;
}

2、把當前日期和時間寫入到檔案中

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

int main(void)
{
    FILE *fp;
    
    time_t current = time(NULL);
    struct tm *timer = localtime(&current);
    
    
 
if((fp = fopen("a.txt", "w")) == NULL)
        printf("\aFile open failed.\n");
    else
    {
        fprintf(fp, "%d-%d-%d; week: %d; %d-%d-%d\n",
        timer -> tm_year + 1900,
        timer -> tm_mon + 1,
        timer -> tm_mday,
        timer -> tm_wday,
        timer -> tm_hour,
        timer 
 
-> tm_min,
        timer -> tm_sec);
        fclose(fp); 
    }
    return 0;
}