#include <iostream>
#include <string>

using namespace std;
typedef const char * String;
#define MAX_CHILDREN 10

class Component{
public:
    String name;
    Component(String name):name(name){}
    virtual void Add(Component *c)=0;
    virtual void Remove(Component *c)=0;
    virtual void Display(int depth)=0;
};

class Composite:public Component{
    Component *children[MAX_CHILDREN];
public:
    Composite(String name):Component(name){
        for(int i=0;i<MAX_CHILDREN;i++) children[i]= 0;
    }
    ~Composite(){
        for(int i=0;i<MAX_CHILDREN;i++){
            if (children[i]) delete children[i];
        }
    }
    void Add(Component *component){
        for(int i=0;i<MAX_CHILDREN;i++){
            if(!children[i]){
                children[i] = component;
                break;
            }
        }
    }
    void Remove(Component *component){
        Component **pc;
        pc = children;
        for(int i=0;i<MAX_CHILDREN;i++){
            if (pc[i]==component){
                for(int j=i;j<(MAX_CHILDREN-1);j++){
                    pc[j] = pc[j+1];
                }
                pc[MAX_CHILDREN-1] = 0;
                break;
            }
        }
    }
    void Display(int depth){
        for(int i=0;i<depth;i++) cout<<'-';
        cout<<name<<endl;
        for(int i=0;i<MAX_CHILDREN;i++){
            if (children[i]) children[i]->Display(depth+2);
        }
    }
};

class Leaf:public Component{
public:
    Leaf(String name):Component(name){}

    void Add(Component *c){
        cout<<"Cannot add to a leaf"<<endl;
    }

    void Remove(Component *c){
        cout<<"Cannot remove from a leaf"<<endl;
    }

    void Display(int depth){
    for(int i=0;i<depth;i++) cout<<'-';
    cout<<name<<endl;}
};

main()
{
    //Create a tree struct
    Component *root = new Composite("root");
    root->Add(new Leaf("Leaf A"));
    root->Add(new Leaf("Leaf B"));

    Composite *comp = new Composite("Composite X");
    comp->Add(new Leaf("Leaf XA"));
    comp->Add(new Leaf("Leaf XB"));

    root->Add(comp);
    root->Add(new Leaf("Leaf C"));

    //add and remove a leaf
    Leaf *leaf = new Leaf("Leaf D");
    root->Add(leaf);
    root->Remove(leaf);
    delete leaf;

    //recursively display tree
    root->Display(1);delete root;
    return 0;
}