class X;
    class Y
    {
            public:
                    Y(const X & x){cout<<"In Y"<<endl;}
    };
    class X
    {
            public:
                    operator Y()const{cout<<"In X"<<endl;}
    };
    void fun(Y y)
    {     cout<<"In fun"<<endl; }
    int main()
    {     X x;
         fun(x);
    }

can any one throw some light on this c++ program ...please i am new to c++