Getting Started with C#

C# is a modern, object-oriented programming language developed by Microsoft. It’s widely used for building desktop applications, web apps, games, and software using the .NET framework.

As a software engineering student, I started learning C# and .NET through Microsoft learn and other resources.

This blog is my personal learning journal where I document what I study, practice, and build.

1) Write the first C# code 🚀 :

Today, I wrote my very first C# program, and I noticed a few important things that might seem small, but they really matter!

Console.WriteLine("Hello World!");

• C# is case-sensitive, which means Console.WriteLine it must be written exactly with the correct casing. Writing console.writeline will result in an error.

• A semicolon (;) is required at the end of each statement.

• Console.WriteLine() prints the output with a line break. To print without a line break, use Console.Write() instead.

2) Data Types🗒️:

• char → Stores a single character, e.g., 'A'

• int → Stores whole numbers, e.g., 123

• string → Stores text, e.g., "Hello World"

• float → Stores decimal numbers (less precision), e.g., 0.2f

• double → Stores decimal numbers (more precision), e.g., 3.1457

• decimal → Used for high-precision calculations, e.g., 12.345m

• bool → Stores true or false values

Console.WriteLine('A');  //Char
Console.WriteLine(123);  //Int
Console.WriteLine("Hello World!");  //String
Console.WriteLine(0.2f);  //float
Console.WriteLine(3.1457); //double
Console.WriteLine(12.345m);  //Decimal
Console.WriteLine(true); //bool

3) Variables🚩:

Here are a few important things about C# variables:

• Can contain alphanumeric characters and the underscore(‘_‘) character

• Special characters are not allowed(‘$‘, ‘#‘)

• Must begin with a letter or underscore. Can’t begin with a Number

• Case sensitive. (“Name” and “name“ are two different variables.)

• Names must not be keywords

String name = "Chathush";
Console.WriteLine(name);

Implicit type of local variable(Var):

An implicit type of variable is created using var Keyword. The var keyword tells the C# compiler that the assigned value implies the data type.

We can change the assigned value after this type of variable.

var name = "Chathush";
Console.WriteLine(name);

You can also print variables in this way,

var name = "Chathush";
var count = 3;

Console.WriteLine($"Hello, {name}! You have {count} cars");
// Output -> Hello, Chathush! You have 3 cars

4) Type Casting 🎗️ :

Explicit casting:

double myDl = 3.14;
int myInt = (int) myDl; 

Console.WriteLine(myInt);
// output -> 3

Type conversion methods:

There are some built-in methods in C# for type casting. Such as,

• ToBoolean()

• ToDouble()

• ToString()

• ToInt32()

• ToInt64()

double myNum = 3.14;

Console.WriteLine(Convert.ToInt32(myNum));
// output -> 3

5) Get User Inputs 🔤 :

We use Console.ReadLine() for getting input from the user. It always returns a String type of value. Therefore for if we need any calculation from inputs, we must typecast the input to the appropriate data type.

Console.WriteLine("Enter your name: ");
String name = Console.ReadLine();

5) C# Math🔢 :

C# has many built-in methods for doing mathematical calculations.

• Math.max(x,y) → Find the maximum value

• Math.min(x,y) → Find the minimum value

• Math.sqrt(x) → Return the square root of ‘x‘

• Math.abs(-3.14) → Return absolute value(Postive value)

• Math.round(9.56) → Round the number to the nearest whole number

6) Loops ➿ :

If you used loops in other languages, C# loops are the same as those.

Type of loops:

• for loop

    for (int i = 0; i < 5; i++)
    {
        Console.WriteLine("Count: " + i);
    }
  

• while loop

    int i = 0;
    while (i < 5)
    {
        Console.WriteLine("While Loop: " + i);
        i++;
    }
  

• do-while loop

    int i = 0;
    do
    {
        Console.WriteLine("Do While Loop: " + i);
        i++;
    }
    while (i < 5);
  

• foreach loop

    string[] fruits = { "Apple", "Banana", "Cherry" };
    foreach (string fruit in fruits)
    {
        Console.WriteLine(fruit);
    }
  

My thoughts 🧠:

Learning C# has been exciting and a bit challenging, but I’m enjoying every part of it.

If you’re also learning C# or just starting out, feel free to follow my blog for regular updates.

Thanks for reading 👋 !

I’m Chathush, a Software Engineering student sharing my journey of learning .NET from scratch.