软件设计⑩③|享元模式

一、效果

二、类图

三、效果

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

typedef enum PieceColorTag
{
    BLACK,
    WHITE
}PIECECOLOR;

class CPiece
{
public:
    CPiece(PIECECOLOR color) : color(color) {}
    PIECECOLOR GetColor() { return color; }
protected:
    // Internal state
    PIECECOLOR color;
};

class CGomoku : public CPiece
{
public:
    CGomoku(PIECECOLOR color) : CPiece(color) {}
};

class CPieceFactory
{
public:
    CPiece* GetPiece(PIECECOLOR color)
    {
        CPiece* pPiece = NULL;
        if (m_vecPiece.empty())
        {
            pPiece = new CGomoku(color);
            m_vecPiece.push_back(pPiece);
        }
        else
        {
            for (vector<CPiece*>::iterator it = m_vecPiece.begin(); it != m_vecPiece.end(); ++it)
            {
                if ((*it)->GetColor() == color)
                {
                    pPiece = *it;
                    break;
                }
            }
            if (pPiece == NULL)
            {
                pPiece = new CGomoku(color);
                m_vecPiece.push_back(pPiece);
            }
        }
        return pPiece;
    }

    ~CPieceFactory()
    {
        for (vector<CPiece*>::iterator it = m_vecPiece.begin(); it != m_vecPiece.end(); ++it)
        {
            if (*it != NULL)
            {
                delete* it;
                *it = NULL;
            }
        }
    }

private:
    vector<CPiece*> m_vecPiece;
};

class CChessboard
{
public:
    void Draw(CPiece* piece)
    {
        if (piece->GetColor())
        {
            cout << "棋子颜色:白棋" << endl;
        }
        else
        {
            cout << "棋子颜色:黑棋" << endl;
        }
    }
};

int main()
{
    CPieceFactory* pPieceFactory = new CPieceFactory();
    CChessboard* pCheseboard = new CChessboard();

    CPiece* pPiece = pPieceFactory->GetPiece(WHITE);
    pCheseboard->Draw(pPiece);

    pPiece = pPieceFactory->GetPiece(BLACK);
    pCheseboard->Draw(pPiece);

    pPiece = pPieceFactory->GetPiece(WHITE);
    pCheseboard->Draw(pPiece);

    pPiece = pPieceFactory->GetPiece(BLACK);
    pCheseboard->Draw(pPiece);
}

参考：https://www.cnblogs.com/ring1992/p/9593235.html