operator 类型名( ){
  实现转换的语句
}

#include <iostream>
using namespace std;

class Base{
  private:
    float x;
    int y;
  public:
    Base (float xx=0,int yy=0){
      x = xx;
      y = yy;
    }
    operator float (){
      return x;
    }
    operator int (){
      return y;
    }
    void display(){
      cout<<"x is :"<<x<<";y is :"<<y<<endl;
    }
};

int main()
{
  Base base(1.0,2);
  base.display();
  int y= base;
  float x= base;
  cout<<"NewX is :"<<x<<"NewY is:"<<y<<endl;
  return 0;
}

#include <iostream>
using namespace std;

class Base{
  private:
    float x;
    int y;
  public:
    Base (float xx=0,int yy=0){
      x = xx;
      y = yy;
    }
    operator float (){
      return x;
    }
    operator int (){
      return y;
    }
    Base operator ++(){//前置 ++
      x++;
      y++;
      return *this;
    } 
    Base operator --(){
      x--;
      y--;
      return *this;
    }
    Base operator ++(int ){//后置 ++
      Base temp = *this;
      ++(*this);
      return temp;
    }
    Base operator --(int ){
      Base temp = *this;
      --(*this);
      return temp;
    }
    void display(){
      cout<<"x is :"<<x<<";y is :"<<y<<endl;
    }
    
};

int main()
{
  Base base(1.0,1);
  Base tem = base++;
  base.display();
  tem.display(); 
  
  Base base2(1.0,1);
  tem = ++base2;
  base.display();
  tem.display(); 
  return 0;
}