(P14) use of the override keyword

1.override

override Keyword ensures that the overriding function declared in the derived class has the same signature as the virtual function of the base class , It also makes it clear that the virtual function of the base class will be overridden , In this way, the correctness of the rewritten virtual function can be guaranteed , It also improves the readability of the code , and final The same keyword should be written after the method .

• How to use it is as follows ：
  Of the following codes 13 Xing He 22 The row shows the specified parent class to override test() Method , Used override After keyword , Suppose that in the rewriting process, due to misoperation , If you write the wrong function name or function parameter or return value, the compiler will prompt syntax error , Improve the correctness of the program , It reduces the probability of error .

• The purpose is ： Improve program readability

class Base
{
    
public:
    virtual void test()
    {
    
        cout << "Base class...";
    }
};

class Child : public Base
{
    
public:
    void test() override
    {
    
        cout << "Child class...";
    }
};

class GrandChild : public Child
{
    
public:
    void test() override
    {
    
        cout << "Child class...";
    }
};

• Reference resources ：final and override