#include <array>#include <iostream>
class Product { public: void SetFirst(int value) { this->first_ = value; flag_[0] = true; } void SetSecond(int value) { if (!flag_[0]) return; this->second_ = value; flag_[1] = true; } void SetThird(int value) { if (!flag_[0] || !flag_[1]) return; this->third_ = value; flag_[2] = true; } bool IsOk() { return flag_[0] && flag_[1] && flag_[2]; }
 private: std::array<bool, 3> flag_; int first_; int second_; int third_;};
class AbstractBuilder { public: AbstractBuilder() {} virtual ~AbstractBuilder() {}
 virtual void BuildFirst() = 0; virtual void BuildSecond() = 0; virtual void BuildThird() = 0; virtual Product* GetProduct() = 0;};
class ConcreteBuilder : public AbstractBuilder { public: ConcreteBuilder() { this->product_ = new Product(); } ~ConcreteBuilder() { delete this->product_; }
 void BuildFirst() { this->product_->SetFirst(1); } void BuildSecond() { this->product_->SetSecond(2); } void BuildThird() { this->product_->SetThird(3); } Product* GetProduct() { return this->product_; }
 private: Product* product_;};
class Director { public: Director(AbstractBuilder* builder) { this->builder_ = builder; } ~Director() {}
 Product* Construct() { this->builder_->BuildFirst(); this->builder_->BuildSecond(); this->builder_->BuildThird(); return this->builder_->GetProduct(); }
 private: AbstractBuilder* builder_;};
int main() { AbstractBuilder* builder = new ConcreteBuilder(); Director* director = new Director(builder); Product* product = director->Construct(); std::cout << product->IsOk() << std::endl; return 0;}