using System;

public class Program

{

    public static void Main()

    {

        // Primitive types are always passed by value.

        int x = 5;

        Console.WriteLine($"The value of x before calling the pass by value method is {x}");

        UpdateInteger(x);

        Console.WriteLine($"\nThe value of x after calling the pass by value method is still {x}");

        UpdateIntegerByRef(ref x);

        Console.WriteLine($"The value of x after calling the pass by ref method is now {x}");

​

        // Arrays and other objects are always passed by reference.

        string[] names = { "Alysa", "Josh" };

        Console.WriteLine($"\nThe names in the array before calling the update names method are: {string.Join(", ", names)}");

        UpdateNames(names);

        Console.WriteLine($"The names in the array after calling the update names method are: {string.Join(", ", names)}");

    }

    // This method accepts as a parameter an integer.

    // The body of the method will change the value of that parameter passed in.

    // Because primitive types are pass by value, what is being used is a copy 

    // of whatever variable from above was passed in.

    public static void UpdateInteger(int input) 

    { 

        input += 10;

    }

    // Primitive types can be passed by reference, although it is bad practice.

    // Passing something by reference means that we are passing over the actual data.

    public static void UpdateIntegerByRef(ref int input)

    {

        input += 10;

    }

    // All non-primitive types (array, classes, lists, etc.) are automatically reference types.

    // When calling a method, a reference to where the data resides is what is passed, not a copy of the data.

    // If that method acts on the reference, any other parts of the code holding access to that data will see it.

    public static void UpdateNames(string[] names)

    {

        for(int i = 0; i < names.Length; i++)

        {

            names[i] = names[i].ToUpper();

        }

    }

}