C# Variables

C# Variables: Storing Data

Variables are essentially "containers" for storing data values. Whenever you need your program to remember a piece of information, you store it in a variable.

C# is a strongly-typed language. This means you must explicitly declare the type of data a variable will hold when you create it.

Creating (Declaring) Variables

To create a variable, you specify the type and assign it a value:

type variableName = value;

Common Variable Types in C#:

• int - Stores integers (whole numbers), without decimals, such as 123 or -123.
• double - Stores floating point numbers, with decimals, such as 19.99 or -19.99.
• char - Stores single characters, such as 'a' or 'B'. Char values are surrounded by single quotes.
• string - Stores text, such as "Hello World". String values are surrounded by double quotes.
• bool - Stores values with two states: true or false.

Examples of Variables

Let's create one variable of each common type:

using System;

class Program {
  static void Main() {
    int myNum = 50;
    double myDoubleNum = 5.99;
    char myLetter = 'D';
    bool myBool = true;
    string myText = "Hello";
    Console.WriteLine(myNum);
    Console.WriteLine(myDoubleNum);
    Console.WriteLine(myLetter);
    Console.WriteLine(myBool);
    Console.WriteLine(myText);
  }
}

Constants (const)

If you want a variable to store a value that should never change throughout your program, you can use the const keyword. This creates a constant variable. If you try to change it later, C# will throw an error.

const int myNum = 15;
// myNum = 20;  <-- This would cause an error