Single Inheritance:

 #include<iostream>

using namespace std;
//base
class A{
    int a,b;
    public :
        void Add(){
        cout<<"Input a and b:\n";
        cin>>a>>b;
        cout<<"Sum="<<(a+b);
    }
    void Sub(){
        cout<<"\nInput a and b:\n";
        cin>>a>>b;
        cout<<"Sum="<<(a-b);
    }
};

//Child 
class B:public A
{
    public :
        void XYZ(){
    //
    // Add();
}
};

//===========Main=======
int main(){

    B obj;
    obj.Add();

    return 0;
}