template method in C++

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

class Base
{
    void a() {  cout << "a  ";  }
    void c() {  cout << "c  ";  }
    void e() {  cout << "e  ";  }

    virtual void ph1() = 0;
    virtual void ph2() = 0;
  public:
    void execute() {
        a();
        ph1();
        c();
        ph2();
        e();
    }
};

class One: public Base {
    void ph1() {  cout << "b  ";  }
    void ph2() {  cout << "d  ";  }
};

class Two: public Base {
    void ph1() {  cout << "2  ";  }
    void ph2() {  cout << "4  ";  }
};

int main() {
    Base *b = new One();
    b->execute();
    cout << endl;
    delete b;
    
    b = new Two();
    b->execute();
    cout << endl;
    delete b;
}

/*
a  b  c  d  e  
a  2  c  4  e 
*/''
```
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