取得某个进程CPU的占用率

/* percent = (user_time_diff + kernel_time_diff) * 100 / (cpu_num * system_time_diff) */
#include<windows.h>
#include<stdio.h>
#include <pdh.h>
#include <Tlhelp32.h>
int main()
{
    // Find the specified Process
    HANDLE hProcess = NULL;
    PROCESSENTRY32 pe = {sizeof(pe)};
    HANDLE hSnapShot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    BOOL suc = Process32First(hSnapShot, &pe);

    while(suc)
    {
        hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, false, pe.th32ProcessID);
        if(hProcess != NULL)
        {
            if(strcmp(pe.szExeFile, "cpu_test.exe") == 0)
            {
                break;
            }
        }
        CloseHandle(hProcess);
        suc = Process32Next(hSnapShot, &pe);
    }
    // Got it
    if(suc)
    {
        ULARGE_INTEGER ulLastSysTime, ulCurSysTime;
        ULARGE_INTEGER ulStart, ulEnd, 
            ulLastProcKernelTime, ulLastProcUserTime,
            ulCurProcKernelTime, ulCurProcUserTime;
        ULARGE_INTEGER ulKernelTimeUsed ,ulUserTimeUsed, ulSysTimePast;
        SYSTEM_INFO si = {0};
        int iCpuUsage = 0;

        GetSystemInfo(&si);
        GetSystemTimeAsFileTime((PFILETIME)&ulLastSysTime);
        GetProcessTimes(hProcess, (PFILETIME)&ulStart, (PFILETIME)&ulEnd, 
            (PFILETIME)&ulLastProcKernelTime, (PFILETIME)&ulLastProcUserTime);

        while(1)
        {

            Sleep(1000);

            GetProcessTimes(hProcess, (PFILETIME)&ulStart, (PFILETIME)&ulEnd, 
                (PFILETIME)&ulCurProcKernelTime, (PFILETIME)&ulCurProcUserTime);
            GetSystemTimeAsFileTime((PFILETIME)&ulCurSysTime);

            ulKernelTimeUsed.QuadPart = ulCurProcKernelTime.QuadPart - ulLastProcKernelTime.QuadPart;
            ulUserTimeUsed.QuadPart = ulCurProcUserTime.QuadPart - ulLastProcUserTime.QuadPart;
            ulSysTimePast.QuadPart = ulCurSysTime.QuadPart - ulLastSysTime.QuadPart;

            iCpuUsage = (
                (ulKernelTimeUsed.QuadPart + ulUserTimeUsed.QuadPart)*100 /  
                                (float)(si.dwNumberOfProcessors*ulSysTimePast.QuadPart)) + 0.5f
                ;

            printf("\rThe Process use %3d%%", iCpuUsage);

            ulLastSysTime = ulCurSysTime;
            ulLastProcKernelTime = ulCurProcKernelTime;
            ulLastProcUserTime = ulCurProcUserTime;
        }
    }
    return 0;
}