这是我创建倒计时用户申请的具体时间的功能：
我需要用该函数创建一个线程.

功能(倒计时)：

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

void countdown(int second)
{
    int secs = 1;
    time_t unix;
    struct tm * timeinfo;
    time(&unix);
    timeinfo = localtime(&unix);
    int t1 = timeinfo->tm_sec;
    int t2 = timeinfo->tm_sec;
    int i = 0;

    while(1 == 1)
    {
       time(&unix);
       timeinfo = localtime(&unix);
       if((t1 + i)  == timeinfo->tm_sec)
       {
              system("cls");
              printf("Time left %d\n",timeinfo->tm_sec - t2 - second);
              i++;
       }
       if(timeinfo->tm_sec >= (t1 + second))
       {
           system("cls");
           puts("Your time its done");
           break;
       }

    }
}

int main()
{
    int limit;
    printf("How much time would you like (In secs): ");
    scanf("%d",&limit);
    countdown(limit);

    system("PAUSE");
    return 0;
}