c 获得毫秒

Linux系统

使用gettimeofday接口：gettimeofday能得到微秒数，比毫秒还要更精确。
#include <stdio.h>
#include <sys/time.h>
int main() {
    struct timeval start, end;
    gettimeofday( &start, NULL );
    sleep(3);
    gettimeofday( &end, NULL );
    int timeuse = 1000000 * ( end.tv_sec - start.tv_sec ) + end.tv_usec - start.tv_usec;
    printf("time: %d us\n", timeuse);
    return 0;
}

使用ftime接口：
#include <stdio.h>
#include <sys/timeb.h>
long long getSystemTime() {
    struct timeb t;
    ftime(&t);
    return 1000 * t.time + t.millitm;
}
int main() {
    long long start=getSystemTime();
    sleep(3);
    long long end=getSystemTime();

    printf("time: %lld ms\n", end-start);
    return 0;
}





Windows系统

使用GetTickCount接口：
#include <windows.h>
#include <stdio.h>
int main() {
    DWORD start, stop;
   start = GetTickCount();
    Sleep(3000);
    stop = GetTickCount();
    printf("time: %lld ms\n", stop - start);
    return 0;
}
Windows系统下有些编译器使用printf输出64位整数参数要使用%I64d，比如VC。

使用QueryPerformanceX接口：
#include <windows.h>
#include <stdio.h>
int main(){
    LARGE_INTEGER li;
    LONGLONG start, end, freq;
    QueryPerformanceFrequency(&li);
    freq = li.QuadPart;
    QueryPerformanceCounter(&li);
    start = li.QuadPart;
    Sleep(3000);
    QueryPerformanceCounter(&li);
    end = li.QuadPart;
    int useTime =(int)((end - start) * 1000 / freq);
    printf("time: %d ms\n", useTime);
    return 0;
}

使用GetSystemTime接口：
#include <windows.h>
#include <stdio.h>
int main(){
    SYSTEMTIME currentTime;
    GetSystemTime(&currentTime);
    printf("time: %u/%u/%u %u:%u:%u:%u %d\n",           
    currentTime.wYear,currentTime.wMonth,currentTime.wDay,
    currentTime.wHour,currentTime.wMinute,currentTime.wSecond,
    currentTime.wMilliseconds,currentTime.wDayOfWeek);
    return 0;
}