C++学习类教程

 // pointer to classes example
    #include <iostream.h>
    
    class CRectangle {
        int width, height;
      public:
        void set_values (int, int);
        int area (void) {return (width * height);}
    };
    
    void CRectangle::set_values (int a, int b) {
        width = a;
        height = b;
    }
    
    int main () {
        CRectangle a, *b, *c;
        CRectangle * d = new CRectangle[2];
        b= new CRectangle;
        c= &a;
        a.set_values (1,2);
        b->set_values (3,4);
        d->set_values (5,6);
        d[1].set_values (7,8);
        cout << "a area: " << a.area() << endl;
        cout << "*b area: " << b->area() << endl;
        cout << "*c area: " << c->area() << endl;
        cout << "d[0] area: " << d[0].area() << endl;
        cout << "d[1] area: " << d[1].area() << endl;
        return 0;
    }

result:

a area: 2
*b area: 12
*c area: 2
d[0] area: 30
d[1] area: 56 

• *x 读作: pointed by x （由x指向的）
• &x 读作: address of x（x的地址）
• x.y 读作: member y of object x （对象x的成员y）
• (*x).y 读作: member y of object pointed by x（由x指向的对象的成员y）
• x->y 读作: member y of object pointed by x (同上一个等价)
• x[0] 读作: first object pointed by x（由x指向的第一个对象）
• x[1] 读作: second object pointed by x（由x指向的第二个对象）
• x[n] 读作: (n+1)th object pointed by x（由x指向的第n+1个对象）