#include <iostream>using namespace std;#define DESTROY_POINTER(ptr) if (ptr) { delete ptr; ptr = NULL; }class TemplateMethod{public:    void AlgorithmA() { Step1(); Step2(); Step3(); }    void AlgorithmB() { Step3(); Step2(); Step1(); }    protected:    virtual void Step1()=0;    virtual void Step2()=0;    virtual void Step3()=0;};class ConcreteTemplateA : public TemplateMethod{public:    ConcreteTemplateA() {}    ~ConcreteTemplateA() {}protected:    void Step1() { cout<<"ConcreteTemplateA::Step1"<<endl; }    void Step2() { cout<<"ConcreteTemplateA::Step2"<<endl; }    void Step3() { cout<<"ConcreteTemplateA::Step3"<<endl; }};class ConcreteTemplateB : public TemplateMethod{public:    ConcreteTemplateB() {}    ~ConcreteTemplateB() {}protected:    void Step1() { cout<<"ConcreteTemplateB::Step1"<<endl; }    void Step2() { cout<<"ConcreteTemplateB::Step2"<<endl; }    void Step3() { cout<<"ConcreteTemplateB::Step3"<<endl; }};int main(int argc, char *argv[]){    TemplateMethod* pTemplate = NULL;        pTemplate = new ConcreteTemplateA;    pTemplate->AlgorithmA();    DESTROY_POINTER(pTemplate);        pTemplate = new ConcreteTemplateB;    pTemplate->AlgorithmB();    DESTROY_POINTER(pTemplate);        return 0;}