建造者模式

【1】什么是建造者模式？

将一个复杂对象的构建与它的表示分离，使得同样的构建过程可以创建不同的表示。

【2】建造者模式代码示例：

代码示例1：

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

class Person
{
public:
    virtual void createHead() = 0;
    virtual void createHand() = 0;
    virtual void createBody() = 0;
    virtual void createFoot() = 0;
};

class ThinPerson : public Person
{
    void createHead()
    {
        cout << "thin head" << endl;
    }
    void createHand()
    {
        cout << "thin hand" << endl;
    }
    void createBody()
    {
        cout << "thin body" << endl;
    }
    void createFoot()
    {
        cout << "thin foot" << endl;
    }
};

class FatPerson : public Person
{
    void createHead()
    {
        cout << "fat head" << endl;
    }
    void createHand()
    {
        cout << "fat hand" << endl;
    }
    void createBody()
    {
        cout << "fat body" << endl;
    }
    void createFoot()
    {
        cout << "fat foot" << endl;
    }
};


class Director
{
private:
    Person *p;
public:
    Director(Person *temp)
    {
        p = temp;
    }
    void create()
    {
        p->createHead();
        p->createHand();
        p->createBody();
        p->createFoot();
    }
};

//客户端代码：
int main()
{
    Person *p = new FatPerson();
    Person *b = new ThinPerson();
    Director *d = new Director(p);
    Director *s = new Director(b);
    d->create();
    s->create();
    delete d;
    delete p;
    delete s;
    delete b;

    return 0;
}

代码示例2：
#include <string>
#include <iostream>
#include <vector>
using namespace std;

class Product
{
private:
    vector<string> product;
public:
    void add(string str)
    {
        product.push_back(str);
    }
    void show()
    {
        vector<string>::iterator iter = product.begin();
        while (iter != product.end())
        {
            cout << *iter << "  ";
            ++iter;
        }
        cout << endl;
    }
};

class Builder
{
public:
    virtual void builderA() = 0;
    virtual void builderB() = 0;
    virtual Product *getResult() = 0;
};

class ConcreteBuilder1 : public Builder
{
private:
    Product *product;
public:
    ConcreteBuilder1()
    {
        product = new Product();
    }
    virtual void builderA()
    {
        product->add("one");
    }
    virtual void builderB()
    {
        product->add("two");
    }
    virtual Product *getResult()
    {
        return product;
    }
};


class ConcreteBuilder2 : public Builder
{
private:
    Product *product;
public:
    ConcreteBuilder2()
    {
        product = new Product();
    }
    virtual void builderA()
    {
        product->add("A");
    }
    virtual void builderB()
    {
        product->add("B");
    }
    virtual Product *getResult()
    {
        return product;
    }
};

class Director
{
private:
    Product *p;
public:
    void construct(Builder *bd)
    {
        bd->builderA();
        bd->builderB();
        p = bd->getResult();
    }
    Product *getResult()
    {
        return p;
    }
};

int main()
{
    Director *director = new Director();

    Builder *bd1 = new ConcreteBuilder1();
    director->construct(bd1);
    Product *pbd1 = director->getResult();

    pbd1->show();

    return 0;
}