计算程序中某一个函数或算法的执行时间

#include <stdio.h>#include <time.h>#include <stdlib.h>int main(){ long i = 10000000L; clock_t start, finish; double duration; printf( "Time to do %ld empty loops is ", i) ; start = clock(); while( i-- ); finish = clock(); duration = (double)(finish - start) / CLOCKS_PER_SEC; printf( "%f seconds\n", duration ); return 0;}