strategy design pattern.cpp

#include <iostream>
using namespace std;

// Strategy Interface
class Strategy {
public:
    virtual void execute() const = 0;
    virtual ~Strategy() = default;
};

// Concrete Strategy A
class ConcreteStrategyA : public Strategy {
public:
    void execute() const override {
        cout << "Executing Strategy A" << endl;
    }
};

// Concrete Strategy B
class ConcreteStrategyB : public Strategy {
public:
    void execute() const override {
        cout << "Executing Strategy B" << endl;
    }
};

// Context
class Context {
private:
    Strategy* strategy;

public:
    Context(Strategy* strategy = nullptr) : strategy(strategy) {}

    void setStrategy(Strategy* newStrategy) {
        strategy = newStrategy;
    }

    void executeStrategy() const {
        if (strategy) {
            strategy->execute();
        } else {
            cout << "No strategy set" << endl;
        }
    }
};

// Client code
int main() {
    Context context;

    // Using Strategy A
    ConcreteStrategyA strategyA;
    context.setStrategy(&strategyA);
    context.executeStrategy();

    // Using Strategy B
    ConcreteStrategyB strategyB;
    context.setStrategy(&strategyB);
    context.executeStrategy();

    return 0;
}