practice 1

#include <iostream>
using namespace std;
class A {
    protected:
          int v;
    public:
         A () {v = 0; };
         void m1 () {
             v += 10; m2 ();
         };
         void m2 () {
             v += 20;
         };
         int getv () {
             return v;
         };
    };
    class B: public A {
    public:
    void m2 () {
          v += 30;
    };
};
int main (){
    B * Obj = new B ();
    Obj-> m1();
    Obj-> m2();
    cout << Obj-> getv () << endl;
    return 0;
}