1.C++14 版本,程序如下:
#include<iostream> #include<ctime> #include<time.h> #ifdef _WIN32 #include <Windows.h> #else #include <unistd.h> #endif using namespace std; void disptime(const struct tm* ptm); int main() { time_t nowtime; nowtime = time(NULL); cout << nowtime << endl; char* dt = ctime(&nowtime); cout << "本地日期和时间:" << dt << endl; tm* gmtm = gmtime(&nowtime); dt = asctime(gmtm); cout << "utc日期和时间:" << dt << endl; tm* itm = localtime(&nowtime); cout << "年:" << 1900 + itm->tm_year << endl; cout << "月:" << 1 + itm->tm_mon << endl; cout << "日:" << itm->tm_mday << endl; cout << "时间:" << itm->tm_hour << ":"; cout << itm->tm_min <<" :"; cout << itm->tm_sec << endl; //方法1 double beginTime = clock(); Sleep(200); //ms double endTime = clock(); cout << (endTime - beginTime)<<"ms" << endl; //方法2 double start = GetTickCount(); //计时器 Sleep(200); double end = GetTickCount(); double last = end - start; cout << last << "ms" << endl; //方法3 LARGE_INTEGER cpuFreq1; LARGE_INTEGER startTime1; LARGE_INTEGER endTime1; QueryPerformanceFrequency(&cpuFreq1); QueryPerformanceCounter(&startTime1); Sleep(200); QueryPerformanceCounter(&endTime1); double last1 = (((endTime1.QuadPart - startTime1.QuadPart) * 1000000) / cpuFreq1.QuadPart); cout << last1 << " us" << endl; return 0; }
2.如报错请做如下设置:
3.结论:
对比发现,C++计时在误差大概率下在10ms以内;10ms内的计时误差大概率超过10ms。