Value and Reference Types

Data types in C# come in two basic varieties: value or reference types. A value type tends to be smaller and directly references its data, while a reference type tends to be larger and holds reference that indicates where the data is stored. As such a reference type is not so closely linked to its data and several refernces can indicate the same piece of data. Below, we have a program that demonstrates how each of these types works. The char[] is a reference type and both of the data types reference the same array of characters, as this program demonstrates.

Program.cs

using System;

namespace XoaX {
    class Program {
        static void Main(string[] args) {
            // int is a value type
            int i = 9;
            int j = i;
            Console.WriteLine("i = " + i + "  j = " + j);
            i = 12;
            Console.WriteLine("i = " + i + "  j = " + j);
            Console.WriteLine();

            // char[] is a reference type
            char[] caOldName = "Simon".ToCharArray();
            char[] caNewName = caOldName;
            Console.Write("Old Name = ");
            Console.WriteLine(caOldName);
            Console.Write("New Name = ");
            Console.WriteLine(caNewName);
            // Changing the caNewName changes caOldName too!
            caNewName[0] = 'P';
            caNewName[1] = 'e';
            caNewName[2] = 't';
            caNewName[3] = 'e';
            caNewName[4] = 'r';
            Console.Write("Old Name = ");
            Console.WriteLine(caOldName);
            Console.Write("New Name = ");
            Console.WriteLine(caNewName);
            Console.WriteLine();
        }
    }
}

Output

i = 9  j = 9
i = 12  j = 9

Old Name = Simon
New Name = Simon
Old Name = Peter
New Name = Peter

Press any key to continue . . .