C++ Program having functions setmarks inside which 3 subject marks should be set & Make total a friend function inside which all 3 subject marks total will be done

#include<iostream.h>

  class Marks

{

  int a;

  int b;

  int c;

  public:

  void setmarks()

  {

  cout<<"Enter Marks Of Subject ";

  cin>>a>>b>>c;

  }

friend int total(Marks m);

};

int total(Marks m)

{

  return(m.a+m.b+m.c);

}

Void main()

{

  Marks x;

  x.setmarks();

  cout<<total(x);

}