『C++』Temp_2018_12_06

 #include <iostream>
 #include <string>
 using namespace std;

 class Type{
 public:
     string Name;
 };

 class O{
 public:
     virtual void ToString(){
         cout<< "O" << endl;
     }
     virtual Type GetType(){
         Type t;
         t.Name="O";
         return t;
     }
 };

 template<class T>
 class V : public O{
 public:
     V<T>(){

     }
 public:
     void ToString(){
         Type t=T::ClassType();
         cout<< t.Name << endl;
     }
 };

 class D: public V<D>{
 public:
     static Type ClassType(){
         Type t;
         t.Name="D";
         return t;
     }
 public:
     D() { }

     Type GetType(){
         Type t;
         t.Name="D";
         return t;
     }
     void ToString(){
         cout << "DDDD" << endl;
     }
 };

 int main(){
     O* o =new O();
     o->ToString();

     D* d =new D();
     d->ToString();

     cin.get();
 }

     //下面的代码 耗时完全相同 —— 指针类型的转换 完全不浪费任何时间
     cout<<"AAA"<<endl;
     for(long long i=;i< **;i++)  //每秒3.5Y次左右
     {
         //这两种指针转换 性能完全相同
         //O* t =(O*)d;
         O* t = static_cast<O*>(d);
     }
     cout<<"BBB"<<endl;
     for(long long i=;i< **;i++)
     {
     }
     cout<<"CCC"<<endl;