Start programming in C#: your universal tool for games, apps, and web development

What is C# and why should you learn it?

C# (read as "C sharp") is a modern programming language created by Microsoft. It is used to develop applications that run on a variety of platforms: computers, phones, game consoles, and the Internet. It is a powerful and versatile tool that is suitable for both beginners and professional developers.

Where is C# used?

1. Games
   C# is the main language for creating games in the popular Unity game engine. This makes it an ideal choice for those who dream of developing games for PCs, consoles, and mobile devices.

2. Software for Windows
   If you want to create applications for computers with Windows, C# is the best choice. This is the "native" language for the Microsoft platform.

3. Mobile apps
   With the help of technologies like Xamarin, you can write applications for Android and iOS in C#.

4. Web applications
   Using ASP.NET (technology from Microsoft) you can develop powerful and fast websites.

Why learn C#?

1. Easy start
   C# has a clear and logical syntax, so it is easy to learn even for schoolchildren.

2. Wide opportunities
   You can create games, phone apps, websites, and computer programs in C# — one language is suitable for everything.

3. High demand
   Knowledge of C# opens doors in companies that develop games, programs and websites.

4. Microsoft Support
   C# is actively developing, and tools and libraries make development easier and more convenient.

Now that you know why C# is so popular, let's look at its basic concepts and analyze examples that will help you understand how it works.

C# language concepts based on examples

1. Variables and data types

What are variables?
Variables are "boxes" that store data. Each variable has:

• Name (for example, seconds, number),

• Data type (e.g. int for integers, string for text),

• Value, which is stored in it.

Example from the countdown timer:

int seconds = 5; // We store the number of seconds

• int — the data type used for integers.

• seconds — variable name.

• 5 — variable value.

Why is this important?
Variables allow you to store and use data in the program. For example, in the timer, we reduce the value of the variable seconds to count down the time.

2. Terms

What are the conditions?
Conditional operators allow the program to make decisions. The program checks some expression (for example, temperature > 20) and performs certain actions depending on the result.

Example from temperature check:

if (temperature > 20)
{
    Console.WriteLine("It's warm outside.");
}
else if (temperature > 10)
{
    Console.WriteLine("It's cool outside.");
}
else
{
    Console.WriteLine("It's cold outside.");
}

How does it work?

1. if checks the first condition. If it is true (for example, temperature > 20), the code inside {} is executed.

2. If the first condition is false, the program checks else if.

3. If none of the conditions are met, else is triggered.

Why is this important?
The conditions allow the program to respond to the data. For example, in the timer or the game "Guess the number" the program prompts you what to do next.

3. Cycles

What are cycles?
Loops allow you to repeat the same action several times. This is useful when you need to process multiple items or perform a task multiple times.

Example from the game "Guess the number":

while (guess != number)
{
    Console.Write("Your guess: ");
    guess = int.Parse(Console.ReadLine());

    if (guess < number)
    {
        Console.WriteLine("Too low!");
    }
    else if (guess > number)
    {
        Console.WriteLine("Too high!");
    }
    else
    {
        Console.WriteLine("Congratulations! You guessed it!");
    }
}

How does it work?

1. The while loop is executed while the guess != number condition is true (until the user guesses the number).

2. The program requests input, checks it and prompts you what to do next.

Why is this important?
Loops allow you to automate repetitive tasks such as data entry, array processing, or password generation.

4. Functions

What are functions?
Functions are blocks of code that perform a specific task. They allow you to avoid repetition and make the code understandable.

Example from the greeting function:

static void Greet(string name)
{
    Console.WriteLine("Hello, " + name + "!");
}

• Greet — function name.

• string name — the parameter that the function accepts.

• Console.WriteLine("Hello, " + name + "!"); — the code that the function executes.

Why is this important?
Functions help to divide the code into logical parts. For example, if you need to greet different users several times, instead of repeating the code, you simply call the function with the desired name.

Function call:

Greet("Alice"); // Displays: Hello, Alice!
Greet("John");  // Displays: Hello, John!

5. Loops with control structures

What is for?
The for loop is used when you know exactly how many times you need to repeat an action. For example, to generate a password or display messages.

Example from password generation:

for (int i = 0; i < length; i++)
{
    int index = random.Next(chars.Length); // Generating a random index
    password += chars[index]; // Adding a symbol to the password
}

• int i = 0; — start from 0.

• i < length; — continue until i is less than the length of the password.

• i++ — increase i by 1 after each cycle.

Why is this important?
Loops for make it easy to process a data set or perform actions a specified number of times.

6. Working with libraries

What are libraries?
Libraries contain ready-made functions and classes that you can use in your program.

Example from random number generation:

Random random = new Random(); // Creating a random number generator
int number = random.Next(1, 101); // Generate a number from 1 to 100

• Random — built-in class for working with random numbers.

• random.Next(1, 101) returns a random number from 1 to 100.

Why is this important?
Libraries simplify development. You can use ready-made functions instead of writing them from scratch.

7. Input and output processing

How does the program "communicate" with the user?
Data input and output is a key part of any program.

Example from the calculator:

Console.Write("Enter first number: ");
double num1 = double.Parse(Console.ReadLine()); // Read the input and convert it to a number

• Console.Write() displays text without a line break.

• Console.ReadLine() reads the line entered by the user.

• double.Parse() converts a string to a number.

Why is this important?
Input and output processing makes programs interactive. The user enters data, and the program processes it and outputs the result.

Conclusion

C# is a language that combines simplicity and power. You have learned the key concepts:

• variables for data storage,

• conditions for decision-making,

• cycles for repeating actions,

• functions to simplify the code,

• libraries for ready-made solutions,

• input and output for user interaction.

These concepts are the basis of most C# programs. Try writing your own programs using the examples in this article to better understand how it all works!