#include <vector>#include <iostream>using namespace std;#define DO_NOTHING()#define DESTROY_POINTER(ptr) if (ptr) { delete ptr; ptr = NULL; }class Component{    friend class Composite;    friend class Leaf;public:    virtual void Whoami()=0;    virtual void AddChild(Component* pChild)=0;    virtual void Whoareyou(int iIndex)=0;    virtual void Travel(Component* pNode) = 0;    protected:    vector<Component*> m_children;};class Composite : public Component{public:    Composite() {}    ~Composite();    virtual void Whoami() { cout<<"I am a Composite"<<endl; }    virtual void AddChild(Component* pChild) { m_children.push_back(pChild); }    virtual void Whoareyou(int iIndex) { cout<<iIndex<<":"; m_children[iIndex]->Whoami(); }    virtual void Travel(Component* pNode);};class Leaf : public Component{public:    virtual void Whoami() { cout<<"I am a piece of Leaf"<<endl; }    virtual void AddChild(Component* pChild) { DO_NOTHING(); }    virtual void Whoareyou(int iIndex) { DO_NOTHING(); }    virtual void Travel(Component* pNode) { Whoami(); }};Composite::~Composite(){    for (unsigned int i = 0; i < m_children.size(); i++)    {        Component* pTmp = m_children[i];        DESTROY_POINTER(pTmp);    }    m_children.clear();}void Composite::Travel(Component* pNode){    if (!pNode) pNode = this; // self    pNode->Whoami();        if (pNode->m_children.size() == 0) return ;        for (unsigned int i = 0; i < pNode->m_children.size(); i++)    {        Travel(pNode->m_children[i]);    }}int main(int argc, char *argv[]){    Component* pRoot, *pBranch1, *pBranch2;    pRoot = new Composite;    pRoot->AddChild(new Leaf);    pBranch1 = new Composite;    pRoot->AddChild(pBranch1);    pBranch1->AddChild(new Leaf);    pBranch1->AddChild(new Leaf);         pBranch2 = new Composite;    pBranch1->AddChild(pBranch2);    pBranch2->AddChild(new Leaf);    pBranch2->AddChild(new Leaf);    pBranch2->AddChild(new Leaf);    pRoot->Travel(NULL);    DESTROY_POINTER(pRoot);    DESTROY_POINTER(pBranch1);    DESTROY_POINTER(pBranch2);    return 0;}