builder design pattern.cpp

#include <iostream>
#include <string>
using namespace std;

// Product class
class Product {
private:
    string partA;
    string partB;
    string partC;

public:
    void setPartA(const string& part) { partA = part; }
    void setPartB(const string& part) { partB = part; }
    void setPartC(const string& part) { partC = part; }

    void show() const {
        cout << "Product parts: " << partA << ", " << partB << ", " << partC << endl;
    }
};

// Builder Interface
class Builder {
public:
    virtual void buildPartA() = 0;
    virtual void buildPartB() = 0;
    virtual void buildPartC() = 0;
    virtual Product* getResult() = 0;
    virtual ~Builder() = default;
};

// Concrete Builder
class ConcreteBuilder : public Builder {
private:
    Product* product;

public:
    ConcreteBuilder() { product = new Product(); }
    ~ConcreteBuilder() { delete product; }

    void buildPartA() override {
        product->setPartA("Part A");
    }

    void buildPartB() override {
        product->setPartB("Part B");
    }

    void buildPartC() override {
        product->setPartC("Part C");
    }

    Product* getResult() override {
        return product;
    }
};

// Director
class Director {
private:
    Builder* builder;

public:
    void setBuilder(Builder* b) {
        builder = b;
    }

    void construct() {
        builder->buildPartA();
        builder->buildPartB();
        builder->buildPartC();
    }
};

// Client code
int main() {
    Director director;
    ConcreteBuilder builder;

    director.setBuilder(&builder);
    director.construct();

    Product* product = builder.getResult();
    product->show();

    // Clean up
    delete product;

    return 0;
}