1 #include <stdio.h>      /* printf */
 2 #include <time.h>       /* clock_t, clock, CLOCKS_PER_SEC */
 3 #include <math.h>       /* sqrt */
 4 #include <iostream>
 5 using namespace std;
 6 
 7 int frequency_of_primes (int n) {
 8   int i,j;
 9   int freq=n-1;
10   for (i=2; i<=n; ++i) for (j=sqrt(i);j>1;--j) if (i%j==0) {--freq; break;}
11   return freq;
12 }
13 
14 int main ()
15 {
16   clock_t t;
17   int f;
18   t = clock();
19   printf ("Calculating...\n");
20   f = frequency_of_primes (99999);
21   printf ("The number of primes lower than 100,000 is: %d\n",f);
22   t = clock() - t;
23   printf ("It took me %ld clicks (%f seconds).\n",t,((float)t)/CLOCKS_PER_SEC);
24   cout<<t<<","<<(float)t/CLOCKS_PER_SEC;
25   return 0;
26 }

typedef   long   clock_t;

#define CLK_TCK  CLOCKS_PER_SEC

/*
 *作者：侯凯
 *说明：clock()计时函数
 *日期：2013-6-6
*/
#include <ctime> //计时用的头文件
#include <iostream>
using namespace std;

int main()
{
    long i = 10000000L;
    clock_t start, end; 
    
    start = clock(); 
    while( i-- );//需要计时的程序段
    end = clock(); 
    printf("The time was: %f\n", (double)(end - start) / CLK_TCK); 

    system("pause");
    return 0;
}

bool  QueryPerformanceFrequency (LARGE_INTEGER *lpFrequency);
bool  QueryPerformanceCounter (LARGE_INTEGER *lpCount);

typedef union _LARGE_INTEGER
{
     struct
     {
       DWORD LowPart ;// 4字节整型数
        LONG  HighPart;// 4字节整型数
     };
     LONGLONG QuadPart ;// 8字节整型数
     
 }LARGE_INTEGER ;

/*
 *作者：侯凯
 *说明：HpTime类高精度计时
 *日期：2013-6-6
*/
#include "hptime.h"
#include <iostream>
using namespace std;

int main()
{
    long i = 10000000L;
    HpTime hpTime;
    
    while( i-- );//要计时的函数段

     printf("The time was: %f\n", hpTime.sec()); 
    system("pause");
    return 0;
}