计算程序运行时间

需要头文件 time.h   函数：clock_t clock(void)

举例：

#include<stdio.h>

#include<stdlib.h>

#include<time.h>

int main(void)

{

        clock_t begin,finish;

        double   difference;

        begin = clock();

         /*******to do some  operation ********/

                 .................

         /**************** end *******************/

        finish = clock();

        difference = difftime(finish, begin)/CLOCKS_PER_SEC;

        printf("time to do the operation is %f \r\n ", dfiierence);

        return 0; 

}