C++ program for multiple inheritance

#include<iostream.h>
#include<conio.h>
class m{
protected:
int m;
public:
m(){
m=10;
}
};
class n{
protected:
int n;
public:
n(){
n=20;
}
};
class o:public m,public n{
protected:
int o;
public:
o(){
o=30;
}
void showmno();
};
void o::showmno(){
cout<<"M = "<<m<<endl<<"N = "<<n<<endl<<"O = "<<o<<endl;
}
void main(){
clrscr();
o obj;
obj.showmno();
getch();
}