Using friend function find the maximum number from given two numbers from two different classes CPP

Using friend function find the maximum number from given two numbers from two different classes. Write all necessary functions and constructors for the program.

#include <iostream.h>
#include <conio.h>


class Student;

class Teacher
{

	private:
	int salary;
	public:
	void setData(int y)
	{
	    salary=y;
	}
	void getData()
	{
		cout<<"Salary "<<salary<<endl;
	}
	friend int maximum(Teacher ,  Student)

};




class Student
{
	private:
	int saving;
	public:
	void setData(int x )
	{
		saving=x;
	}
	void getData()
	{
		cout<<"Savings "<<saving<<endl;
	}
	friend int maximum(Teacher t, Student s);

};


int maximum(Teacher t, Student s)
{
	if (t.salary >	s.saving)
	{
		return t.salary;
	}
	else
	{
		return s.saving;
	}

}


void main()
{
	clrscr();
	Student s1;
	s1.setData(4000);
	s1.getData();
	Teacher t1;
	t1.setData(5000);
	t1.getData();
	int max =0;
	max=maximum(t1,s1);                        d
	cout<< "Maximum "<<  max <<endl;
	getch();

}