C++如何使用组合模式实现树形结构

#include 
#include 
#include 
#include 

// 抽象组件类
class FileSystemComponent {
public:
    virtual ~FileSystemComponent() = default;
    virtual void display(int depth = 0) const = 0;
};

// 叶子类：文件
class File : public FileSystemComponent {
    std::string name;
public:
    explicit File(const std::string& fileName) : name(fileName) {}

    void display(int depth) const override {
        std::cout << std::string(depth, ' ') << "? " << name << "\n";
    }
};

// 容器类：目录
class Directory : public FileSystemComponent {
    std::string name;
    std::vector> children;

public:
    explicit Directory(const std::string& dirName) : name(dirName) {}

    void add(std::unique_ptr component) {
        children.push_back(std::move(component));
    }

    void display(int depth = 0) const override {
        std::cout << std::string(depth, ' ') << "? " << name << "\n";
        for (const auto& child : children) {
            child->display(depth + 2);
        }
    }
};

int main() {
    // 创建根目录
    auto root = std::make_unique("Root");

    // 添加文件到根目录
    root->add(std::make_unique("main.cpp"));
    root->add(std::make_unique("Makefile"));

    // 创建子目录
    auto srcDir = std::make_unique("src");
    srcDir->add(std::make_unique("utils.cpp"));
    srcDir->add(std::make_unique("main.cpp"));

    auto includeDir = std::make_unique("include");
    includeDir->add(std::make_unique("utils.h"));

    // 将子目录加入根目录
    srcDir->add(std::move(includeDir));
    root->add(std::move(srcDir));

    // 显示整个结构
    root->display();

    return 0;
}