public class Example
{
    public static void ModifyWithRef(ref int x)
    {
        x += 10;
    }

    public static void ModifyWithOut(out int x)
    {
        x = 20;
    }

    public static void Main()
    {
        int a = 5;
        ModifyWithRef(ref a);

        int b = 5;
        ModifyWithOut(out b);

        Console.WriteLine($"Value of a: {a}");
        Console.WriteLine($"Value of b: {b}");
    }
}