What is the Variables in C# ? with free Q/A

What is the Variables in C# ?

Variables are are used to store data that can be manipulated and referenced throughout the program. In C#, variables must be declared with a specific type, which defines the kind of data they can hold. Here’s a detailed introduction to variables in C#, along with an example and line-by-line notes.

Declaration and Initialization

In C#, a variable must be declared before it can be used. The declaration specifies the variable’s type and name. Optionally, the variable can be initialized (assigned a value) at the time of declaration.

Syntax

type variableName = value;

Example

using System;

namespace VariableExample
{
    class Program
    {
        static void Main(string[] args)
        {
            int age = 30;            // Integer variable
            double height = 5.9;     // Double variable
            string name = "John";    // String variable
            bool isActive = true;    // Boolean variable

            Console.WriteLine("Name: " + name);
            Console.WriteLine("Age: " + age);
            Console.WriteLine("Height: " + height);
            Console.WriteLine("Active: " + isActive);
        }
    }
}

Line-by-Line Notes

using System;

This directive includes the System namespace, which contains fundamental classes and base classes that define commonly-used data types, events, and event handlers.

namespace VariableExample

Defines a namespace called “VariableExample” to organize the code and prevent naming conflicts.

class Program

Defines a class named Program. In C#, classes are the basic building blocks for creating objects

static void Main(string[] args)

The Main method is the entry point of the program. It is static because it is called by the runtime without creating an instance of the class. void indicates that the method does not return any value. string[] args is an array of strings that can hold command-line arguments.

int age = 30;

Declares an integer variable named age and initializes it with the value 30.
int: Data type that represents a 32-bit signed integer.
age: Name of the variable.
30: Initial value assigned to age.

double height = 5.9;

Declares a double-precision floating-point variable named height and initializes it with the value 5.9.
double: Data type for double-precision floating-point numbers.
height: Name of the variable.
5.9: Initial value assigned to height.

string name = "John";

Declares a string variable named name and initializes it with the value "John".
string: Data type for a sequence of characters.
name: Name of the variable.
"John": Initial value assigned to name.

bool isActive = true;

Declares a boolean variable named isActive and initializes it with the value true.
bool: Data type for boolean values (true or false).
isActive: Name of the variable.
true: Initial value assigned to isActive.

Console.WriteLine("Name: " + name);

Outputs the value of the name variable to the console.
Console.WriteLine: Method that outputs text to the console.
"Name: " + name: Concatenates the string "Name: " with the value of name.

Console.WriteLine("Age: " + age);

Outputs the value of the age variable to the console.
"Age: " + age: Concatenates the string "Age: " with the value of age.

Console.WriteLine("Height: " + height);

Outputs the value of the height variable to the console.
"Height: " + height: Concatenates the string "Height: " with the value of height.

Console.WriteLine("Active: " + isActive);

Outputs the value of the isActive variable to the console.
"Active: " + isActive: Concatenates the string "Active: " with the value of isActive.

What is the Variables in C# ? with free Q/A