C++ 类的指针

指向C++类的指针与指向结构体的指针的方式完全相同，要访问指向类的指针的成员，您要使用成员访问运算符 **- > ** 运算符，就像使用指向结构体的指针一样。与所有指针一样，您必须在使用之前对指针进行初始化。

让我们尝试下面的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;
}

当上述代码被编译并执行时，它会产生以下结果-

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