using System;
public class Program
{
public static void Main()
Program p=new Program();
int x=5;
int y=4;
int diff;
var res= p.Sum(ref x,y,out diff);
Console.WriteLine("ref value is "+x+"\n out value is "+diff);
}
public int Sum(ref int x,int y,out int diff)
diff=0;
diff=x-y;
return x+y;