using System;

​

class A

{

    public int q;

}

​

public class Program

{

    static void Aaa(A a)

    {

        a.q = 15;

    }

    static void Qqq(ref int q)

    {

        q = 15;

    }

​

    public static void Main()

    {

        var a = new A();

        a.q = 5;

        var q = 5;

        Aaa(a);

        Qqq(ref q);

        Console.WriteLine(a.q);

        Console.WriteLine(q);

​

    }

}