using System;

public class Program

{

    public void Main()

    {

        int myVal = 0;

        myVal = MethodByVal(myVal);

        int myRef = 0;      

        MethodByRef(ref myRef);

        Console.WriteLine("By val: {0}" , myVal); //returns 'By val: 30'

        Console.WriteLine("By ref: {0}" , myRef); //returns 'By ref: 30'

    }

    private int MethodByVal (int intByVal) {

        return intByVal + 30;

    }

    private void MethodByRef (ref int intByRef) {

        intByRef += 30;

    }

}