Hybrid inheritance (overriding base class member functions)

#include<iostream.h>
#include<conio.h>
class student
{
int rlno;
public:
void getData()
{
cout<<"Get Roll Number";
cin>>rlno;
}
void putData()
{
cout<<"Roll Number="<<rlno<<"\n";
}
};
class mark:public student
{
int mark;
public:
void getData()
{
cout<<"Get Mark";
cin>>mark;
}
void putMark()
{
cout<<"Mark="<<mark<<"\n";
}
};
void main()
{
mark M;
M.getData();
M.getData();
M.putData();
M.putMark();
getch();
}

Output:
Get Mark
66
Get Mark
88
Rollno=0
Mark=88