复合设计模式C ++

Question

我的代码在这里给出了分段错误。我不知道为什么会这样。我收到一条警告：＆＃39; FilesystemObject＆＃39;是抽象的但具有非虚拟析构函数。我也尝试将析构函数设为虚拟，但这似乎没有任何帮助。

#include<iostream>
#include<list>
using namespace std;

class FilesystemObject{
public:
    virtual void print()=0;
};

class File: public FilesystemObject{
public:
    File(const string& filename) : fileName(filename) {}
    void print() {
        cout<< fileName << endl;
    }
private:
    string fileName;
};

class Directory: public FilesystemObject {
public:
    Directory(const string& path) : dirPath(path) {}
    ~Directory() {
        for_each(children_.begin(),children_.end(), FilesystemObjectDeallocator());
    }
    void print() {
        cout<<"Printing Directory Filenames"<<dirPath<<endl;
        for(list<FilesystemObject*>::iterator it = children_.begin(), itend = children_.end(); it!=itend; ++it)
            (*it)->print();
    }
    void add(FilesystemObject* object) {
        children_.push_back(object);
    }
    void remove(FilesystemObject* object) {
        list<FilesystemObject*>::iterator found = find(children_.begin(), children_.end(),object);
        if(found!=children_.end())
            children_.erase(found);
    }
    private:
        list<FilesystemObject*> children_;
        string dirPath;
        struct FilesystemObjectDeallocator {
            void operator()(FilesystemObject*& p) {
                delete p;
            }
        };
    };

    int main(int argc, char* argv[]) {
        File* file1 = new File("test1");
        File* file2 = new File("test2");
        File* file3 = new File("test3");
        Directory* directory1 = new Directory("/root");
        Directory* directory2 = new Directory("/username");
        directory2->add(file1);
        directory2->add(file2);
        directory1->add(file3);
        directory1->add(directory2);
        directory2->add(directory1);
        directory1->print();
        return 0;
    }