复习笔记

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考完了c++，上传一点笔记，以便寒假的时候，继续复习！
1.#include<iostream>using namespace std; //静态成员的初始化，虽然有可能成为全局变量，但因为是static，所以仍是安全的//int x=100;//class Ws//{//static int x;//static int y;//public ://void print () const //{//cout <<"ws::x "<<x<<endl;//cout<<"ws::y "<<y<<endl;//}//};//int Ws::x =1;//int Ws::y =x+1;//int x=100;//int y=x+1;//int main()//{//Ws s;//s.print ();//return 0;//}2.//模板定义，其中用到了运算符重载template <class T>class Array{enum{size =100};T A [size];public :T& operator [](int index);};template<class T>T& Array<T>::operator [](int index){if(index>=0&&index<size)return A[index];}int main(){Array<float> fa;fa[0]=1.11111;cout<<fa[0]<<endl;}3.#include<iostream>using namespace std;//实现向上转化，不需加virtual，加virtual，实现晚捆绑作用=动态捆绑(根据对象类型);与3统一enum note{middlec,csharp,cflat};class instrument{public :virtual void play(note) const{cout <<"instrument::play"<<endl;}};class wind :public instrument{public :void play(note )const {cout <<"wind : paly"<<endl;}};void tune(instrument & i)//先调用派生类{i.play (middlec);}int main(){wind flute;tune (flute);}4.//虚拟函数解决基类、派生类同名函数的调用<-windows编程#include<iostream.h>class Base{public: virtual void virtualf(void){cout<<"here is Base\n";}};class derived:public Base{public :void virtualf(void){cout<<"here is Derived\n";}};void main(){Base * ptr,Base;derived derivedobject;ptr=&Base;ptr->virtualf ();ptr=&derivedobject;ptr->virtualf() ;}