C++的四种强制类型转换static_cast、dynamic_cast、const_cast、reinterpret_cast在类指针中的应用

1. static_cast

   #include < iostream>
   class Base
   {
   public:
   Base(int c = 9,double a=7.99999):_c( c),_a(a){}
   public:
   int _c;
   double _a;
   };
   class Derived:public Base
   {
   public:
   int _d;
   double _e;
   float _ff;
   char _cc;
   };
   int main(void)
   {
   Base base;
   Derived *drvPtrA = static_cast<Derived *>(&base);
   /1.无编译告警，但是危险操作，譬如说调用drvPtrA->_d会造成不可预知的后果,因为还没初始值/
   /派生类指针指向基类对象/

   std::cout<_a<<std::endl;
   std::cout<_c<<std::endl;
   std::cout<_d<<std::endl;
   std::cout<_e<<std::endl;
   std::cout<_ff<<std::endl;
   std::cout<_cc<<std::endl;
   /*这里Derived drvPtrA可访问派生类及其基类的成员/
   system(“pause”);
   }

2. dynamic_cast

3. const_cast

4. reinterpret_cast