# Introduction to Programming Languages and Tools of the Trade
This lesson covers the basics of programming languages. The topics covered here apply to most modern programming languages today. In the 'Tools of the Trade' section, you'll learn about useful software that helps you as a developer.
> You can take this lesson on [Microsoft Learn](https://docs.microsoft.com/learn/modules/web-development-101/introduction-programming/?WT.mc_id=academic-77807-sagibbon)!
Programming (also known as coding) is the process of writing instructions for a device such as a computer or mobile device. We write these instructions with a programming language, which is then interpreted by the device. These sets of instructions may be referred to by various names, but *program*, *computer program*, *application (app)*, and *executable* are a few popular names.
A *program* can be anything that is written with code; websites, games, and phone apps are programs. While it's possible to create a program without writing code, the underlying logic is interpreted by the device and that logic was most likely written with code. A program that is *running* or *executing* code is carrying out instructions. The device that you're reading this lesson with is running a program to print it to your screen.
Programming languages enable developers to write instructions for a device. Devices can only understand binary (1s and 0s), and for *most* developers that's not a very efficient way to communicate. Programming languages are the vehicle for communication between humans and computers.
Programming languages come in different formats and may serve different purposes. For example, JavaScript is primarily used for web applications, while Bash is primarily used for operating systems.
*Low level languages* typically require fewer steps than *high level languages* for a device to interpret instructions. However, what makes high level languages popular is their readability and support. JavaScript is considered a high level language.
✅ A Fibonacci sequence is [defined](https://en.wikipedia.org/wiki/Fibonacci_number) as a set of numbers such that each number is the sum of the two preceding ones, starting from 0 and 1. The first 10 numbers following the Fibonacci sequence are 0, 1, 1, 2, 3, 5, 8, 13, 21 and 34.
A single instruction in a program is called a *statement* and will usually have a character or line spacing that marks where the instruction ends, or *terminates*. How a program terminates varies with each language.
Statements within a program may rely on data provided by a user or elsewhere to carry out instructions. Data can change how a program behaves, so programming languages come with a way to temporarily store data so that it can be used later. These are called *variables*. Variables are statements that instruct a device to save data in its memory. Variables in programs are similar to variables in algebra, where they have a unique name and their value may change over time.
There's a chance that some statements will not be executed by a device. This is usually by design when written by the developer or by accident when an unexpected error occurs. This type of control over an application makes it more robust and maintainable. Typically, these changes in control happen when certain conditions are met. A common statement used in modern programming to control how a program runs is the `if..else` statement.
A **development environment** is a unique set of tools and features that a developer uses often when writing software. Some of these tools have been customized for a developer's specific needs, and may change over time if that developer changes priorities in work, personal projects, or when they use a different programming language. Development environments are as unique as the developers who use them.
- *Debugging* helps uncover bugs and errors by stepping through the code, line by line. Some editors have debugging capabilities; they can be customized and added for specific programming languages.
- *Syntax highlighting* adds colors and text formatting to code, making it easier to read. Most editors allow customized syntax highlighting.
- *Extensions and Integrations* are specialized tools for developers, by developers. These tools weren't built into the base editor. For example, many developers document their code to explain how it works. They may install a spell check extension to help find typos within the documentation. Most extensions are intended for use within a specific editor, and most editors come with a way to search for available extensions.
- *Customization* enables developers to create a unique development environment to suit their needs. Most editors are extremely customizable and may also allow developers to create custom extensions.
Another crucial tool is the browser. Web developers rely on the browser to see how their code runs on the web. It's also used to display the visual elements of a web page that are written in the editor, like HTML.
Many browsers come with *developer tools* (DevTools) that contain a set of helpful features and information to help developers collect and capture important information about their application. For example: If a web page has errors, it's sometimes helpful to know when they occurred. DevTools in a browser can be configured to capture this information.
Some developers prefer a less graphical view for their daily tasks and rely on the command line to achieve this. Writing code requires a significant amount of typing and some developers prefer to not disrupt their flow on the keyboard. They will use keyboard shortcuts to swap between desktop windows, work on different files, and use tools. Most tasks can be completed with a mouse, but one benefit of using the command line is that a lot can be done with command line tools without the need of swapping between the mouse and keyboard. Another benefit of the command line is that they're configurable and you can save a custom configuration, change it later, and import it to other development machines. Because development environments are so unique to each developer, some will avoid using the command line, some will rely on it entirely, and some prefer a mix of the two.
- [Command Line](https://docs.microsoft.com/windows-server/administration/windows-commands/windows-commands/?WT.mc_id=academic-77807-sagibbon) (also known as CMD) 💻
When a developer wants to learn something new, they'll most likely turn to documentation to learn how to use it. Developers often rely on documentation to guide them through how to use tools and languages properly, and also to gain deeper knowledge of how it works.
- [Mozilla Developer Network (MDN)](https://developer.mozilla.org/docs/Web), from Mozilla, the publishers of the [Firefox](https://www.mozilla.org/firefox/) browser
- [Web.dev](https://web.dev), from Google, publishers of [Chrome](https://www.google.com/chrome/)
- [Microsoft's own developer docs](https://docs.microsoft.com/microsoft-edge/#microsoft-edge-for-developers), for [Microsoft Edge](https://www.microsoft.com/edge)
Study a bit on the different languages available to the programmer. Try to write a line in one language, and then rewrite it in two others. What did you learn?
