重载运算符的显式调用和默认调用

namespace D{    
    class cnum{
        public:
            double Val;
            cnum(double n): Val(n){
            }
            operator double() {
                return this->Val;
            }
    };

    class num{
        public:
            double Val;
            num(double n): Val(n) {
            }
            
             // 重载强制类型运算符 
            operator int(){
                return this->Val;
            }
            operator double() {
                return this->Val;
            }
            operator cnum(){
                cnum c(this->Val);
                cout<<"进入 class num的cnum转换...."<<endl;
                return c;
            }
    };
    
    class bnum{
        public:
            double Val;
            bnum(double n): Val(n) {
            }
            operator num(){
                num n(this->Val);
                return n;
            }
    };
    
    void dmain(){
        num n1(11.66);
        double d1 = double(n1);
        int i1 = (int)n1;
        cout << &d1 << "\t" << d1 << endl;
        cout << &i1 << "\t" << i1 << endl;        
        
        bnum b1(10.88);
         n1 = num(b1);
         cout << b1.Val << "\t" << &b1.Val << endl;
        cout << n1.Val << "\t" << &n1.Val << endl;
        
        cnum c1(8.66);
        
        //c1 =n1.operator cnum();  调用成功 这种事显示调用，最安全 
        c1=n1;//调用成功，这种也会转换成上面那种 
        
        cout << c1.Val << "\t" << &c1.Val << endl;
    }
}