#include <map>
#include <iostream>
#include <string>
#include <vector>
#include <climits>
#include <algorithm>
#include <math.h>
#include <utility>
using namespace std;

class A
{

  public:
    A()
        : a1(2)
    {
        int i = 0;
        ++i;
    }
    virtual int do1() { return 1; }
    virtual int do2() { return 2; }
    int a1;
};

class B : public A
{
  public:
    B()
        : b1(2)
    {
        int i = 0;
        ++i;
    }

    virtual int do1() { return 3; }
    int b1;
    int b2;
};

class C : public virtual A
{
  public:
    C()
        : c1(2)
    {
        int i = 0;
        ++i;
    }
    virtual int do1() { return 4; }
    int c1;
};

int main()
{
    A *a = new A;
    B *b = new B;
    C *c = new C;

    A *ab = b;
    b->do1();
    A *ac = c;
}