Multiple Inheritance in C++

There is lot of confusion in multiple or multi-level inheritance as it should be for studying OOPs as inheritance is important for it.

* /program to illustrate multiple inheritance./ *
#include < iostream > using namespace std;
class M
{
    protected: int m;
    public: void get(int);
};
class N
{
    protected: int n;
    public: void getdata(int);
};
class P: public M, public N
{
    public: void display(void);
};
void M::get(int x)
{
    m = x;
}
void N::getdata(int y)
{
    n = y;
}
void P::display(void)
{
    cout << "\nm=" << m;
    cout << "\nn=" << n;
    cout << "\nm * n:" << m * n;
}
int main()
{
    P obj;
    obj.get(10);
    obj.getdata(20);
    obj.display();
    return 0;
}