# Chapter 1. First Steps in Programming

In this chapter, we are going to find out what programming is in its core and how to write simple programs and apps.

• We will get familiar with the idea of programming languages and development platforms, along with concepts like compilation and code execution.
• We are going to look at the environments for software development (IDEs) and how to work with them, in particular with Visual Studio.
• We will write and execute our first program with the programming language C# in Visual Studio.
• We will exercise with a couple of tasks: we will create console-based programs, a graphical application (GUI) and a Web application.
• We will learn how to check the correctness of the solutions from this book in the Judge system of SoftUni.
• We will get to know some of the typical mistakes, which are often made during code writing and how to prevent doing them.

## Video: Chapter Overview

Watch a video lesson about what we shall learn in this chapter here: https://youtu.be/6RVKMlXtWg4.

## Introduction to Coding by Examples

Coding means to write commands for the computer, e.g.

Console.WriteLine("Welcome to coding");


Run the above code example: https://repl.it/@nakov/welcome-to-coding-csharp.

When executed, the above command prints the following text:

Welcome to coding


Several commands can be written as a sequence, called "computer program":

var size = 5;
Console.WriteLine("Size = " + size);
Console.WriteLine("Area = " + size * size);


Run the above code example: https://repl.it/@nakov/square-area-csharp.

The result (output) from the above program is as follows:

Size = 5
Area = 25


The above program (sequence of commands) consists of 3 commands:

1. Defines a variable size and stores an integer value 5 in it.
2. Prints the value of the variable a, along with some text.
3. Calculates and prints the value of the expression a * a.

Let's explain in greater detail what is programming, what is programing language, how to write commands and simple programs in the C# language, using the Visual Studio development environment.