How to Declaration and assign of variable in C# ~ Dot Net Labs

Sunday 4 June 2023

How to Declaration and assign of variable in C#

Variable

Variable is a named storage location that holds a value of a particular data type. It is used to store and manipulate data during the execution of a program. Variables have a specific type, which determines the kind of data they can hold, such as integers, floating-point numbers, characters, Boolean values, or custom types.

In C#, variables can be of different types, each representing a specific kind of data. Here are some commonly used types of variables in C#:

Numeric Types:

int: Represents whole numbers (e.g., 42).
float: Represents single-precision floating-point numbers (e.g., 3.14f).
double: Represents double-precision floating-point numbers (e.g., 3.14).
decimal: Represents decimal numbers with higher precision (e.g., 3.14m).
byte: Represents unsigned integers (0 to 255).
short: Represents small integers (-32,768 to 32,767).
long: Represents large integers (-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807).

Character Types:

char: Represents a single character (e.g., 'A', '5', '$').

Boolean Type:

bool: Represents a Boolean value (either true or false).

String Type:

string: Represents a sequence of characters (e.g., "Hello, World!").

Enumerations:

enum: Represents a set of named values (e.g., days of the week, months).

Arrays:

type[]: Represents a collection of elements of a specific type (e.g., int[], string[]).

Object Type:

object: Represents any type of data (a reference to an instance of a class).

Create Variables

You can declare variables using the following syntax:

<type> <variableName>;

Here's an example of declaring variables of different types in C#:

int age; // declaring an integer variable named "age"
float temperature; // declaring a float variable named "temperature"
bool isStudent; // declaring a boolean variable named "isStudent"
string name; // declaring a string variable named "name"

You can also declare and initialize a variable in a single statement:

<type> <variableName> = <value>;

Here's an example:

int count = 0; // declaring and initializing an integer variable named "count" with a value of 0
float pi = 3.14f; // declaring and initializing a float variable named "pi" with a value of 3.14
bool isActive = true; // declaring and initializing a boolean variable named "isActive" with a value of true
string message = "Hello, world!"; // declaring and initializing a string variable named "message" with a value of "Hello, world!"

It's important to note that the variable name should follow certain rules:

It must start with a letter or underscore (_).
It can contain letters, digits, and underscores.
It cannot contain spaces or special characters (except underscores).

It's also recommended to use meaningful names for variables to make your code more readable and maintainable.

A demonstration of how to declare variables of different types with a screenshot:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace VariableDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            string Name = "Amit Kumar";
            int Age = 50;
            float num1 = 85.45f;
            double num2 = 524.2;
            char ch = 'A';

            Console.WriteLine("All information are :");
            Console.WriteLine(Name);
            Console.WriteLine(Age);
            Console.WriteLine(num1);
            Console.WriteLine(num2);
            Console.WriteLine(ch);

            Console.ReadLine();

        }
    }
}

Output: