How do I implement Visitor pattern?

The Visitor pattern is a design pattern that lets you separate algorithms from the objects on which they operate.

This pattern is used when you have a set of classes with differing interfaces and you want to perform operations on these classes.


#include <iostream>

// Forward declarations
class ConcreteElementA;
class ConcreteElementB;

// Visitor Interface
class Visitor {
public:
    virtual void visit(ConcreteElementA* element) = 0;
    virtual void visit(ConcreteElementB* element) = 0;
};

// Element Interface
class Element {
public:
    virtual void accept(Visitor* visitor) = 0;
};

// Concrete Elements
class ConcreteElementA : public Element {
public:
    void accept(Visitor* visitor) override {
        visitor->visit(this);
    }
    void operationA() {
        std::cout << "Operation A in ConcreteElementA\n";
    }
};

class ConcreteElementB : public Element {
public:
    void accept(Visitor* visitor) override {
        visitor->visit(this);
    }
    void operationB() {
        std::cout << "Operation B in ConcreteElementB\n";
    }
};

// Concrete Visitor
class ConcreteVisitor : public Visitor {
public:
    void visit(ConcreteElementA* element) override {
        element->operationA();
    }

    void visit(ConcreteElementB* element) override {
        element->operationB();
    }
};

// Client Code
int main() {
    ConcreteElementA elementA;
    ConcreteElementB elementB;

    ConcreteVisitor visitor;

    elementA.accept(&visitor);
    elementB.accept(&visitor);

    return 0;
}

How do I implement Visitor pattern?

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How do I implement Visitor pattern?

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