operator T()提供了一个本类型到T的隐式转换,不允许使用参数
`class B
{
private:
int _b;
public:
B(int b):_b(b){}
~B(){}
const int getB()const{return _b;}
bool operator ==(B& b){
return _b == b.getB();
}
};
class A
{
private:
int _a;
public:
A(/* args */){}
A(int a):_a(a){}
~A(){}
const int getA(){return _a;}
operator B(){
std::cout<<"good"<<std::endl;
return B(this->_a);
}
};`