dyncast1.cpp

来自「本课程主要介绍面向对象程序设计的方法和c++语言的基本概念。以c++语言中的面向」· C++ 代码 · 共 43 行

//dyncast1.cpp
//dynamic cast used to test type of object
//RTTI must be enabled in compiler
#include <iostream>
#include <typeinfo>           //for dynamic_cast
using namespace std;
////////////////////////////////////////////////////////////////
class Base
   { 
   virtual void vertFunc()    //needed for dynamic cast
      {  }
   };
class Derv1 : public Base
   {  };
class Derv2 : public Base
   {  };
////////////////////////////////////////////////////////////////
//checks if pUnknown points to a Derv1
bool isDerv1(Base* pUnknown)  //unknown subclass of Base
   {
   Derv1* pDerv1;
   if( pDerv1 = dynamic_cast<Derv1*>(pUnknown) )
      return true;
   else
      return false;
   }
//--------------------------------------------------------------
int main()
   {
   Derv1* d1 = new Derv1;
   Derv2* d2 = new Derv2;

   if( isDerv1(d1) )
      cout << "d1 is a member of the Derv1 class\n";
   else
      cout << "d1 is not a member of the Derv1 class\n";

   if( isDerv1(d2) )
      cout << "d2 is a member of the Derv1 class\n";
   else
      cout << "d2 is not a member of the Derv1 class\n";
   return 0;
   }