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Occasions for C++ function rewriting: compliance between subclass requirements and parent class interface

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2024-05-02 14:42:01906browse

Function rewriting means that a subclass creates a different implementation of a function with the same name as its parent class. It is usually used in the following situations: the subclass has specific requirements that are not covered by the parent class. Subclasses need to modify the behavior of parent class functions. The principle of interface isolation requires that parent class interfaces be decomposed into smaller sub-interfaces.

C++ 函数重写的场合:子类需求与父类接口的契合

C Occasions for function rewriting: Matching of subclass requirements and parent class interface

What is function rewriting Write?

Function overriding means that a subclass creates a function with the same name as its parent class but different implementations. Through overriding, a subclass can extend or modify the parent class's behavior to meet its specific needs.

Occasions of function rewriting

Function rewriting is usually used in the following situations:

  • The subclass has a parent class that has not been Specific needs covered.
  • The subclass needs to modify the behavior of the parent class function.
  • The Interface Segregation Principle (ISP) requires that parent class interfaces be decomposed into smaller sub-interfaces.

Practical case

Consider the following parent and subclasses:

class Animal {
public:
  virtual void speak() { cout << "Generic animal sound" << endl; }
};

class Dog : public Animal {
public:
  virtual void speak() override { cout << "Woof!" << endl; }
};

In the Dog class , we rewrote the speak() function. This allows the Dog object to speak in a "Woof!" manner, while the Animal object still emits the "Generic animal sound".

Notes

The following are some notes on function rewriting:

  • The overridden function must have the same name as the parent class function Name and signature (including parameter and return value types).
  • Overriding functions must use the override keyword to explicitly indicate that it is a function override.
  • Overriding functions can have different implementations, but cannot change the visibility (public, protected, or private) of the parent class function.

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