Pointer to C++ Classes

指向C ++类的指针与指向结构的指针完全相同，并且可以访问指向使用成员访问运算符的类的指针成员-》运算符，就像使用指向结构的指针一样。 与所有指针一样，您必须在使用之前初始化指针。

让我们尝试以下示例来理解指向类的指针的概念 -

#include <iostream>
using namespace std;
class Box {
   public:
      // Constructor definition
      Box(double l = 2.0, double b = 2.0, double h = 2.0) {
         cout <<"Constructor called." << endl;
         length = l;
         breadth = b;
         height = h;
      }
      double Volume() {
         return length * breadth * height;
      }
   private:
      double length;     // Length of a box
      double breadth;    // Breadth of a box
      double height;     // Height of a box
};
int main(void) {
   Box Box1(3.3, 1.2, 1.5);    // Declare box1
   Box Box2(8.5, 6.0, 2.0);    // Declare box2
   Box *ptrBox;                // Declare pointer to a class.
   // Save the address of first object
   ptrBox = &Box1;
   // Now try to access a member using member access operator
   cout << "Volume of Box1: " << ptrBox->Volume() << endl;
   // Save the address of second object
   ptrBox = &Box2;
   // Now try to access a member using member access operator
   cout << "Volume of Box2: " << ptrBox->Volume() << endl;
   return 0;
}

编译并执行上述代码时，会产生以下结果 -

Constructor called.
Constructor called.
Volume of Box1: 5.94
Volume of Box2: 102