c_cpp 在C ++中进行强制转换和向下转换

Posted 2021-05-14

#include <iostream>

//c++ down/up casting clases example

//base struct
struct Base
{
  int type;
  Base* next;
  Base* prev;
  
  int getType()
  {
    return type;
  }
};

struct IntObj: Base
{
  long value;
  IntObj(long val): value(val) {  }
  
  long getValue()
  {
    return value;
  }
};



int main() {
  Base* b = new IntObj(8);
  std::cout << b->getType() << "\n";
  //static cast needed for down casting
  IntObj* i = static_cast<IntObj*>(b);
  //or a reinterpret_cast 
  IntObj* j = reinterpret_cast<IntObj*>(b);
  std::cout << j->getValue() << "\n";
}