0. C++代码运行时间统计(精确到纳秒(ns)):
#include <iostream> #include <chrono> #include <iomanip> using namespace std; void main() { auto start = chrono::high_resolution_clock::now(); //开始时间 double db = 0; //此处放代码 for (int i = 0; i < 100000; i++) { db += i; } auto end = chrono::high_resolution_clock::now(); //结束时间 __int64 duration = (end - start).count(); cout << "程序运行时间:" << setprecision(10) << duration / 1000000000.0 << "s" << "; " << duration / 1000000.0 << "ms" << "; " << duration / 1000.0 << "us" << endl; cin.get(); }
运行结果:
1. C++代码运行时间统计:
#include <iostream> #include <thread> //包含此头文件 using namespace std; void main() { clock_t start = clock(); for (int i = 0; i < 1000; i++) { cout << "hello" << endl; } clock_t end = clock(); cout << "程序运行时间:" << end - start << "ms" << endl; cin.get(); }
2. C/C++中计算代码运行时间:
方法一:单位ms
#include<iostream> #include<Windows.h> using namespace std; int main() { DWORD start_time = GetTickCount(); //开始时间; GetTickCount()获取从操作系统启动开始所经过的毫秒数,返回值是DWORD类型 for (int i = 0; i < 100000000; i++) { i++; } DWORD end_time = GetTickCount(); //结束时间; cout << "运行时间为:" << (end_time - start_time) << "ms" << endl; system("pause"); return 0; }
方法二:单位s
#include <iostream> #include <ctime> using namespace std; void main(void) { clock_t start, finish; double duration; start = clock(); //开始时间; clock()是C/C++中的计时函数,而与其相关的数据类型是clock_t for(int i=0;i<100;i++) cout << "hello world" << endl; finish = clock(); //结束时间; duration = (double)(finish - start) / CLOCKS_PER_SEC; //代码运行时间 cout <<"代码运行时间为:"<< duration << " s" << endl; system("pause"); }