1. Primitive Types (Value Types)

Primitive types represent single values and are stored directly in memory.

2. Non-Primitive Types (Reference Types)

Non-primitive types are more complex data types that can store collections of values or more complex data structures. They are stored as references in memory.

3. Nullable Types

C# also supports nullable types, which allow value types to represent an undefined state. This is done using the ? syntax.

• Example: int? can hold an integer value or null.

4. Enums

• enum: A special "value type" that enables a variable to be a set of predefined constants.

5. Dynamic Type

• dynamic: A type that bypasses compile-time type checking, allowing you to work with variables that can change types at runtime.

Examples :

1. Value Types

Integral Types

csharp
1int age = 30;          // 32-bit signed integer
2long population = 7800000000L; // 64-bit signed integer
3short temperature = -5; // 16-bit signed integer
4byte score = 255;      // 8-bit unsigned integer

Floating Point Types

csharp
1float height = 5.9f;  // 32-bit single-precision floating-point
2double weight = 70.5; // 64-bit double-precision floating-point
3decimal price = 19.99m; // 128-bit precise decimal for financial calculations

Other Value Types

csharp
1char initial = 'A';   // A single 16-bit Unicode character
2bool isActive = true; // Boolean value

2. Reference Types

String

csharp
1string name = "John Doe"; // A sequence of characters

Arrays

csharp
1int[] numbers = { 1, 2, 3, 4, 5 }; // An array of integers

Class

csharp
1public class Person
2{
3    public string Name { get; set; }
4    public int Age { get; set; }
5}
6
7Person person = new Person(); // Creating an instance of the Person class
8person.Name = "Alice";
9person.Age = 28;

Object

csharp
1object obj = "Hello, World!"; // Object can hold any data type

3. Nullable Types

csharp
1int? nullableInt = null; // Nullable integer, can hold an integer or null

4. Enums

csharp
1public enum Days
2{
3    Sunday,
4    Monday,
5    Tuesday,
6    Wednesday,
7    Thursday,
8    Friday,
9    Saturday
10}
11
12Days today = Days.Wednesday; // Using the enum

5. Dynamic Type

csharp
1dynamic dynamicVar = 10; // Initially an integer
2dynamicVar = "Now I'm a string"; // Can change to a string at runtime

Full Example

Here’s a complete example that incorporates several of these data types:

csharp
1using System;
2
3class Program
4{
5    public enum Days
6    {
7        Sunday,
8        Monday,
9        Tuesday,
10        Wednesday,
11        Thursday,
12        Friday,
13        Saturday
14    }
15
16    static void Main()
17    {
18        // Value Types
19        int age = 30;
20        float height = 5.9f;
21        bool isStudent = false;
22
23        // Reference Types
24        string name = "Alice";
25        int[] scores = { 85, 90, 78 };
26
27        // Nullable Type
28        int? optionalValue = null;
29
30        // Enum
31        Days today = Days.Wednesday;
32
33        // Dynamic Type
34        dynamic dynamicVar = 100;
35        Console.WriteLine(dynamicVar); // Outputs: 100
36        dynamicVar = "Changed to a string";
37        Console.WriteLine(dynamicVar); // Outputs: Changed to a string
38
39        // Output
40        Console.WriteLine($"Name: {name}, Age: {age}, Height: {height}, Is Student: {isStudent}");
41        Console.WriteLine($"Scores: {string.Join(", ", scores)}");
42        Console.WriteLine($"Optional Value: {optionalValue}");
43        Console.WriteLine($"Today is: {today}");
44    }
45}

Explanation

• The program defines an enum for days of the week.
• It demonstrates the use of various value types (like int, float, and bool), reference types (like string and arrays), nullable types, and dynamic types.
• It prints out the values of these variables to the console.