如何使用clock（）函数获取运行时间

#include <stdio.h>
#include <time.h>
int main()
{
  time_t startTime, endTime;
  while(1)
  {
    startTime = clock();
    /*
       Some processing
    */
    endTime = clock();
    gap = (int)((endTime - startTime) / (CLOCKS_PER_SEC));
    printf("StartTime: %d, EndTime: %d\n", (int)startTime, (int)endTime);
    printf("RunningTime: %d sec", gap);
  }
}
#include <stdio.h>
#include <time.h>
int main()