构造优化

// CmdLine.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"const int kMillion = 1000;class Base {public:Base(int id) { id_ = 2; }void compute() { id_ *= 400; }private:int id_;};class Derived: public Base {public:Derived(int id):Base(id) {}};#include "tick_counter.h"#include <iostream>using namespace std;int _tmain(int argc, _TCHAR* argv[]) {TickCounter counter1;for (int i = 0; i < 10; ++i) {counter1.start();for (int i = 0; i < kMillion; ++i) { Derived child(1);child.compute(); }unsigned __int64 time1 = counter1.stop();cout << time1 << endl;TickCounter counter2;counter2.start();for (int i = 0; i < kMillion; ++i) { Base child(1);child.compute();//i = i +2; }unsigned __int64 time2 = counter2.stop();cout << time2 << endl;cout << "==========================" << endl;}getchar();return 0;} 

Debug版效率有50%提升。Release 版执行速度无太大差别。VC编译器的优化相当彻底。