How to correctly use virtual methods in c++?

by monroe.bahringer , in category: General Help , 2 months ago

How to correctly use virtual methods in c++?

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1 answer

by keegan.towne , 2 months ago

@monroe.bahringer 

To correctly use virtual methods in C++, follow these steps:

  1. Declare the base class: Start by declaring a base class that contains at least one virtual function. For example:
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class Base {
public:
    virtual void doSomething();
};


  1. Implement the virtual method: Define the virtual function in the base class. It can be either inside the class declaration or in a separate implementation file. For example:
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void Base::doSomething() {
    // Implementation goes here
}


  1. Create derived classes: Create derived classes that inherit from the base class. The derived classes should override the virtual function if they need to provide their own implementation. For example:
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class Derived1 : public Base {
public:
    void doSomething() override;
};

class Derived2 : public Base {
public:
    void doSomething() override;
};


  1. Implement virtual methods in derived classes: Provide the implementation for the virtual function in each derived class as needed. For example:
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void Derived1::doSomething() {
    // Implementation for Derived1 goes here
}

void Derived2::doSomething() {
    // Implementation for Derived2 goes here
}


  1. Use polymorphism: You can then create objects of the base class or any derived class and use them interchangeably. The correct implementation of the virtual function will be called based on the actual object type. For example:
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Base* obj1 = new Derived1();
Base* obj2 = new Derived2();

obj1->doSomething(); // Calls Derived1::doSomething()
obj2->doSomething(); // Calls Derived2::doSomething()


Remember to deallocate memory properly to prevent memory leaks.