How is the usage of c++ override?

In C++, “override” is a function modifier that explicitly declares a member function as overriding a virtual function in the base class.

In C++, when a function is declared as virtual in a base class, derived classes can choose whether to override this function. Using the keyword “override” can improve code readability and ensure that the compiler can detect override errors.

The syntax for using override is as follows:

class Base {
public:
    virtual void foo();
};

class Derived : public Base {
public:
    void foo() override; // 使用override显式地重写Base中的foo函数
};

In the above example, the Derived class explicitly overrides the foo function in the Base class and marks it with the override keyword. If the foo function is not overridden in the Derived class, or if the overridden function’s signature does not match the virtual function in the base class, the compiler will generate an error.

The benefit of using the override keyword is:

1. This has improved the readability and maintainability of the code, clearly indicating that this function is for overriding virtual functions in the base class.
2. The compiler can detect overwriting errors at compilation time, such as mismatched function signatures.
3. replace with a new action or decision

It should be noted that the override keyword can only be used to override virtual functions in derived classes, and cannot be used for non-virtual or static functions. Additionally, the final keyword introduced in C++11 can be used to prevent derived classes from overriding virtual functions.