 #include "stdafx.h"
#include <conio.h>
#include <iostream>
#include <string>
using namespace std;
using namespace std;
class CParent
   {
 public:
  CParent(){}
//以下在構(gòu)造函數(shù)是初始化成員列表,多個(gè)用逗號(hào)隔開
CParent(string strName,int age):strName(strName),m_age(age){}
virtual string GetName(){return strName;}
private:
string strName;
int m_age;
 };
class CChild:public CParent
{
public:
//初始化成員列表父類與本類的成員
//加入explicit關(guān)鍵字,防止隱式類型轉(zhuǎn)換
explicit CChild(string strName):CParent("Parent:"+strName,34),strName("Child:"+strName){}
string GetName(){return strName;}
private:
string strName;
};
int _tmain(int argc, _TCHAR* argv[])
{
int pause;
//調(diào)用父類構(gòu)造
CParent parent("parent",56);
cout<<parent.GetName()<<endl;
//調(diào)用子類構(gòu)造
CChild child("sky");
cout<<child.GetName()<<endl;
//子類構(gòu)造有加explicit,不可以穩(wěn)式轉(zhuǎn)換
//CChild child1 = "explicitTest";
//cout<<child1.GetName()<<endl;
//1.static_cast類型轉(zhuǎn)換
//a.指針轉(zhuǎn)換
CParent *pParent=NULL;
pParent = static_cast<CParent*>(&child) ;
cout<<pParent->GetName()<<endl;//調(diào)用的是CChild類的GetName
//b.對(duì)象間轉(zhuǎn)換
CParent tmpParent;
//tmpParent = (CParent)child;
tmpParent = static_cast<CParent>(child) ;
cout<<tmpParent.GetName()<<endl;//調(diào)用的是父類GetName,因?yàn)閠mpParent是Cparent對(duì)象
//虛表不起作用
//2.dynamic_cast類型轉(zhuǎn)換
CChild *pChild1;
CChild *pChild2;
pChild1 = dynamic_cast<CChild*>(&parent);//將返回空指針
pChild2 = static_cast<CChild*>(&parent); //返回的是parent地址.但調(diào)用子類的方法,將不安全
/**//*dynamic_cast支持交叉轉(zhuǎn)換
如果B繼承A,C也繼承A.
那么將B用static_cast轉(zhuǎn)成C是編譯錯(cuò)誤
將B用dynamic_cast轉(zhuǎn)成C返回NULL指針
 */
//3.const_cast
const CParent *constParent=NULL;
CParent *pParent1 = const_cast<CParent*>(constParent);
//4.reinterpret_cast
//最底層的重新解釋
//reinterpret_cast原原本本的位復(fù)制,而static_cast有內(nèi)部解析轉(zhuǎn)換
int n=9;
double d1=reinterpret_cast<double & > (n);
cout<<d1<<endl;
double d2 = static_cast<double>(n);
cout<<d2<<endl;
_getch();
return 0;
}
|