factory

工厂模式是什么

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示例题目的代码

cpp:

# include <iostream>
# include <vector>
# include <memory>

using namespace std;

class Block
{
public:
    virtual void produce() = 0;
    virtual ~Block() = default;
};

class circleBlock: public Block
{
public:
    void produce() override
    {
        cout << "Circle Block" << endl;
    }
};

class squareBlock: public Block
{
public:
    void produce() override
    {
        cout << "Square Block" << endl;
    }
};

class BlockFactory
{
public:
    virtual unique_ptr<Block> createBlock() = 0;
    virtual ~BlockFactory() = default;
};

class circleBlockFactory: public BlockFactory
{
public:
    unique_ptr<Block> createBlock() override
    {
        return make_unique<circleBlock>();
    }
};

class squareBlockFactory: public BlockFactory
{
public:
    unique_ptr<Block> createBlock() override
    {
        return make_unique<squareBlock>();
    }
};

class BlockFactorySystem
{
private:
    vector<unique_ptr<Block>> blocks;

public:
    void produceBlocks(BlockFactory* factory, int quantity)
    {
        for (int i = 0; i < quantity; i++)
        {
            auto block = factory->createBlock();
            block->produce();
            blocks.push_back(move(block));
        }
    }
};

int main()
{
    BlockFactorySystem factorySystem;
    int productCount;

    cin >> productCount;

    for (int i = 0; i < productCount; i++)
    {
        string blockType;
        int blockNum;

        cin >> blockType >> blockNum;

        if (blockType == "Circle")
        {
            circleBlockFactory circle;
            factorySystem.produceBlocks(&circle, blockNum);
        }
        else
        {
            squareBlockFactory square;
            factorySystem.produceBlocks(&square, blockNum);
        }
    }

    return 0;
}