[Object-oriented programming in C++ mainly includes the three core concepts of encapsulation, inheritance and polymorphism]

Object-oriented programming in C++ mainly includes the three core concepts of encapsulation, inheritance and polymorphism.

1. Encapsulation :

   • Encapsulation is a mechanism in object-oriented programming that bundles data (properties) and functions (methods) that operate on the data into a single unit (class).
   • The main purpose of encapsulation is to hide implementation details so that external code cannot directly access the internal representation of the object.
   • By using access modifiers such as private, protectedand public, we can control the access level of members of a class.
   • Encapsulation enhances code security and simplifies interfaces. External code uses the public interface to interact with the object without caring about the internal implementation details.

   class Box {
        
         
         
   private:
       double length;  // 私有属性
   public:
       void