享元模式

一、截图

 二、代码示例

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

//棋子的颜色
enum PieceColor { BLACK, WHTIE };
//棋子的位置
struct PiecePos {
    int m_x;
    int m_y;
    PiecePos(int a, int b) :m_x(a), m_y(b) {}
};

class Piece {

public:
    Piece(PieceColor color) : m_color(color) {

    }
    ~Piece() {}
    virtual void draw() {}
protected:
    PieceColor m_color;
    
};

class BlackPiece :public Piece {
public:
    BlackPiece(PieceColor color) :Piece(color) {}
    ~BlackPiece() {}
    void draw() { cout << "绘制一个黑棋 " << endl; }
};
class WhitePiece :public Piece {
public:
    WhitePiece(PieceColor color) :Piece(color) {}
    ~WhitePiece() {}
    void draw() { cout << "绘制一个白棋 " << endl; }
};

class PieceBoard {
public:
    PieceBoard(string black, string white) :m_blackName(black), m_WhiteName(white) {
        m_pBlackPiece = nullptr;
        m_pWhitePiece = nullptr;
    }
    ~PieceBoard()
    {
        clear();
    }
    void setPiece(PieceColor color, PiecePos pos) {
        
        if (color == BLACK) {
            if(m_pBlackPiece == nullptr)
                m_pBlackPiece = new BlackPiece(color);
            
            cout << m_blackName << "在" << pos.m_x << "," << pos.m_y << "下了一步" << endl;
            m_pBlackPiece->draw();
        }
        else {
            if(m_pWhitePiece == nullptr)
                m_pWhitePiece = new WhitePiece(color);
            
            
            cout << m_WhiteName << "在" << pos.m_x << "," << pos.m_y << "下了一步" << endl;
            m_pWhitePiece->draw();
        }
        m_vecPiece.push_back(pos);
    }
    void clear() {
        delete m_pBlackPiece;
        delete m_pWhitePiece;
    }
private:
    vector<PiecePos> m_vecPiece;//棋盘上的棋子,
    string m_blackName;
    string m_WhiteName;
    Piece* m_pBlackPiece;
    Piece* m_pWhitePiece;
};


int main(void) {
    
    PieceBoard pieceBoard("laoxia", "laoding");
    pieceBoard.setPiece(BLACK, PiecePos(44, 37));
    pieceBoard.setPiece(WHTIE, PiecePos(19, 70));
    pieceBoard.setPiece(BLACK, PiecePos(1, 1));
    pieceBoard.setPiece(WHTIE, PiecePos(2, 2));
    system("pause");
    return 0;
}