C++如何实现享元模式管理大量对象

void display(int x, int y) const override {
    std::cout << "Draw '" << symbol << "' at (" << x << "," << y 
              << ") with font=" << font << ", size=" << size << "\n";
}

<H3>享元工厂管理实例</H3>
<p>使用静态map缓存已创建的享元对象，避免重复生成：</p>
```cpp
class FlyweightFactory {
private:
    static std::map<std::string, std::shared_ptr<CharacterFlyweight>> pool;

public:
    static std::shared_ptr<CharacterFlyweight> getCharacter(
        char symbol, const std::string& font, int size) {

        std::string key = std::string(1, symbol) + "_" + font + "_" + std::to_string(size);

        if (pool.find(key) == pool.end()) {
            pool[key] = std::make_shared<ConcreteCharacter>(symbol, font, size);
        }

        return pool[key];
    }
};

// 静态成员定义
std::map<std::string, std::shared_ptr<CharacterFlyweight>> FlyweightFactory::pool;

ch1->display(0, 0);   // 外部状态不同
ch2->display(10, 0);  // 但共享内部状态
ch3->display(20, 0);

return 0;

<p>输出显示虽然创建了三个逻辑字符，但'A'只有一份内部数据，节省了存储空间。</p>

<p>基本上就这些。关键在于分离变与不变的部分，用工厂控制实例唯一性，适合处理重复度高的细粒度对象。</p>