Understanding Programming Languages: A Comprehensive Crash Course

Introduction

Technology encompasses a vast array of fields, and within programming, the sheer number of languages available can be daunting, particularly for beginners. This chapter provides a crash course on programming languages, exploring many modern options, their strengths, and underlying concepts. We will delve into the distinctions between low-level and high-level languages, compiled versus interpreted languages, and statically typed versus dynamically typed languages. This overview aims to provide valuable insights for newcomers and experienced programmers alike who are considering learning a new language.

Levels of Programming Languages: Low-Level vs. High-Level

When discussing the “level” of a programming language, we are essentially comparing how closely the code we write is to what the computer’s hardware, specifically the Central Processing Unit (CPU), understands. Computers do not directly understand languages like JavaScript, C#, or Java. These languages must be translated into a format that the CPU can process.

CPU (Central Processing Unit): The primary component of a computer that processes instructions and performs calculations. It is often referred to as the “brain” of the computer.

Therefore, the “level” of a language refers to its proximity to the hardware and the degree of abstraction present.

Machine Language: The Lowest Level

At the very bottom, closest to the hardware, is machine language, also known as machine code.

Machine Language (Machine Code): The most fundamental level of programming language, consisting of binary code (sequences of 0s and 1s) that directly instructs a computer’s CPU.

• Machine code is the absolute lowest level of code.
• It comprises instructions that directly control the CPU.
• These instructions are purely numeric, represented as binary (0s and 1s).
• While binary is machine-readable, it is difficult for humans. Machine code can also be represented in hexadecimal, a base-16 number system, for improved human readability.

Hexadecimal: A base-16 number system used in computing as a more human-readable way to represent binary data. It uses digits 0-9 and letters A-F to represent values.

• Machines process only binary because it directly corresponds to electrical states (on or off).

Programmers no longer write machine code directly due to its tedious and error-prone nature.

Assembly Language: A Step Above Machine Code

The next level up is assembly language (ASM).

Assembly Language: A low-level programming language that uses symbolic representations (mnemonics) for machine instructions. It provides a more human-readable alternative to machine code while still offering direct hardware control.

• Assembly language uses numbers, symbols, and abbreviations instead of just 0s and 1s.
• Assembly code is not compiled in the same way as higher-level languages. Instead, it is assembled into executable machine code by an assembler.

Assembler: A program that translates assembly language code into machine code that can be directly executed by a computer’s CPU.

• Assembling is a simpler process compared to compiling, which is used for higher-level languages.

Compiling: The process of translating source code written in a high-level programming language into machine code or bytecode that can be executed by a computer.

• Learning assembly language provides valuable insight into how software interacts with the CPU and hardware.
• Today, assembly language is primarily used for developing firmware and software for embedded systems.

Firmware: A type of software that is embedded into hardware devices, providing low-level control and instructions for the device’s operation. It is often stored in non-volatile memory like ROM or flash memory.

Embedded Systems: Specialized computer systems designed to perform specific tasks within a larger device or system. Examples include microcontrollers in appliances, cars, and industrial equipment.

General-Purpose Languages: Bridging the Gap

Moving further up, we encounter general-purpose languages like C and C++.

General-Purpose Language: A programming language designed to be versatile and applicable to a wide range of programming tasks, rather than being specialized for a particular domain.

• In some contexts, especially when compared to machine and assembly language, these are referred to as “high-level languages.”
• However, relative to languages like Python or Java, they are considered “lower-level.”

C: The Foundation

C is considered the lowest-level general-purpose language, with only assembly and machine code being lower.

• Created in the early 1970s by Dennis Ritchie, derived from the language “B.”
• Used to develop the UNIX operating system.
• C is a procedural language, contrasting with object-oriented languages.

Procedural Language: A programming paradigm that focuses on structuring programs as a sequence of procedures or functions that perform specific tasks. Code is organized into blocks of instructions that are executed in a linear fashion.

Object-Oriented Language: A programming paradigm that organizes code around “objects,” which are instances of “classes.” Objects encapsulate data (properties) and behavior (methods), promoting modularity, reusability, and abstraction.

• Being lower-level, C requires manual management of hardware resources like memory allocation.

Memory Allocation: The process of reserving a portion of a computer’s memory to store data or instructions during program execution. In lower-level languages, programmers often have manual control over this process.

• C is powerful and versatile, used for:
  • Operating systems (e.g., Windows kernel)
  • Compilers for other languages
  • Device drivers
  • Database systems
  • Various powerful programs
• C is a compiled language.

Compiled vs. Interpreted Languages

Before proceeding, it’s essential to understand the difference between compiled and interpreted languages.

• Compiled Languages: Require a compiler to translate the source code into machine code.

Compiler: A software tool that translates source code written in a high-level programming language into machine code or bytecode before program execution. The compiled code is then executed directly by the computer.

*   The compiler processes the code into machine-understandable instructions.
*   The resulting compiled program is not human-readable and is executed directly by the CPU.
*   Lower-level compiled languages like C often require manual memory management, offering greater hardware control but increased complexity.
*   Compiled languages generally result in faster runtime execution due to direct machine code execution.

• Interpreted Languages: Do not directly compile to machine code. An interpreter is used to execute the code line by line.

Interpreter: A software tool that executes source code line by line at runtime. It reads and executes instructions directly, without a separate compilation step into machine code.

*   The source code is processed through an interpreter during execution.
*   Languages like Python and Ruby are often first compiled into **bytecode**, an intermediate form, before being executed by a **virtual machine**.

Bytecode: An intermediate form of code that is created after the source code is compiled but before it is executed by a virtual machine. It is platform-independent and designed to be executed by an interpreter or virtual machine.

Virtual Machine: A software environment that emulates a computer system, allowing programs written in bytecode or other intermediate forms to run on different platforms. The Java Virtual Machine (JVM) and Python Virtual Machine (PVM) are examples.

*   While technically having a compilation step to bytecode, these are generally categorized as **interpreted or scripting languages**.

Scripting Language: Often used interchangeably with “interpreted language,” referring to languages designed for automating tasks, controlling applications, and creating dynamic content. They are typically higher-level and easier to use than compiled languages.

*   Interpreted languages are typically easier to work with and enable faster code writing (faster write time).
*   However, they introduce more abstraction, and the execution process can be slower at runtime compared to compiled languages because of the interpretation step.

The choice between compiled and interpreted languages involves trade-offs, balancing development speed and ease with runtime performance.

C++: Object-Oriented Powerhouse

C++ was created in the 1980s as a superset of C, meaning it includes all of C’s features and adds more tools.

Superset: In programming languages, a language A is a superset of language B if it includes all features of B and adds additional features. C++ is a superset of C.

• C++ is object-oriented, introducing the concept of objects and classes.
• Like C, C++ does not have garbage collection, requiring manual memory management.

Garbage Collection: An automatic memory management process in some programming languages that reclaims memory occupied by objects that are no longer in use by the program. This relieves programmers from manually freeing memory.

• C++ is incredibly powerful, used for:
  • AAA gaming titles
  • Operating systems
  • Virtual Reality (VR)
  • Robotics
  • Scientific computing

Rust: Modern Performance and Safety

Rust is a relatively newer language emphasizing both low-level control and high performance, while also prioritizing memory safety.

• Provides higher-level capabilities than C and C++ but with memory safety features to reduce errors.
• Does not have garbage collection, but offers built-in memory safety mechanisms.
• Rust’s applications include:
  • Game engines
  • Operating systems
  • Browser components
  • VR applications
  • Web servers and back-end web development (APIs, microservices) using frameworks like Rocket.
• Rust is gaining traction in WebAssembly (Wasm).

WebAssembly (Wasm): A binary instruction format for a stack-based virtual machine. It is designed for high performance in web browsers, enabling near-native speed execution of code written in languages like C++, Rust, and others.

*   Wasm is a new type of bytecode for modern browsers, offering significantly higher performance than JavaScript.
*   Languages like C++ and Rust can be compiled to Wasm.
*   Wasm has significant potential for gaming and video tools within browsers.

Higher-Level, Interpreted Languages: Ease of Use and Rapid Development

Moving to even higher-level languages, many of which are interpreted, sacrifices some runtime speed for increased ease of use and faster development. These are particularly popular in web development.

Java: Write Once, Run Anywhere

Java is a high-level, class-based, object-oriented programming language.

Class-Based: Refers to object-oriented programming languages where objects are created as instances of classes, which define the structure and behavior of objects.

• Everything in Java is an object or part of an object, defined by classes.
• Classes contain variables (properties) and functions (methods).

Properties (Variables): In object-oriented programming, properties, also known as attributes or fields, are data associated with an object that describe its state.

Methods (Functions): In object-oriented programming, methods, also known as functions or operations, are actions or behaviors that an object can perform.

• Java is known for its “write once, run anywhere” capability.
• Compiled Java code can run on any platform with Java support without recompilation, thanks to the Java Virtual Machine (JVM).

JVM (Java Virtual Machine): A virtual machine that enables Java bytecode to run on various operating systems. It provides a platform-independent runtime environment for Java applications.

• Java is compiled into bytecode for the JVM.
• Applications of Java include:
  • Desktop applications (Graphical User Interface - GUI)
  • Enterprise applications
  • Web servers and APIs
  • Android mobile app development
  • Large-scale business applications (used by companies like Spotify, LinkedIn, Amazon)
  • Games (e.g., Minecraft)
• Java is statically typed.

Static vs. Dynamic Typing

Static typing and dynamic typing are important distinctions in programming languages.

• Statically Typed Languages: Type checking is performed at compile time.

Statically Typed: A programming language paradigm where the data type of variables is checked and enforced at compile time. This requires explicit declaration of variable types in the code, enhancing code reliability and catching type-related errors early.

*   Data types must be explicitly defined in the code for variables and function returns (e.g., specifying a variable as a string).
*   Once a type is assigned, it cannot change (e.g., a string cannot become a boolean).
*   Languages discussed so far (C, C++, Rust, Java, C#) are statically typed.
*   Statically typed languages can be more robust and less prone to type-related errors.

• Dynamically Typed Languages: Type checking is done at runtime.

Dynamically Typed: A programming language paradigm where data types of variables are checked and enforced during program execution (runtime), not at compile time. Variable types are inferred automatically, offering flexibility but potentially leading to runtime type errors.

*   Types are not explicitly defined; the language infers the type automatically at runtime.
*   Examples include JavaScript and Python (discussed later).
*   Dynamically typed languages require less code related to type declarations, but may be more prone to runtime type errors.

TypeScript is an example of adding static typing to a dynamically typed language (JavaScript).

Kotlin: Modern JVM Language

Kotlin is another language that runs on the JVM, often considered a modern alternative to Java.

• Also used for Android app development; favored for modern native Android apps.
• Often considered easier to learn than Java.
• Can be used for object-oriented or procedural programming.
• Applications extend beyond mobile, including web servers, data science, and more.
• Companies using Kotlin include Cash App, VMware, and PlanGrid.

C#: Microsoft’s Versatile Language

C# is a compiled and statically typed language, developed by Microsoft.

• Unlike C and C++, C# has garbage collection, simplifying memory management.
• Object-oriented, with syntax similar to Java.
• Part of the .NET Framework, a software development framework by Microsoft.

.NET Framework: A software development framework developed by Microsoft for building and running applications on Windows. It provides a comprehensive set of libraries and tools for various programming tasks, including web, desktop, and mobile development.

• C# can be used with other .NET languages like Visual Basic and F#.
• While called a compiled language, C# compiles to Intermediate Language (IL), not directly to machine code.

IL (Intermediate Language): An intermediate, platform-independent bytecode language into which source code is compiled in the .NET framework. It is then further compiled or interpreted by the Common Language Runtime (CLR) to execute on a specific platform.

• C# uses the Common Language Runtime (CLR) environment.

CLR (Common Language Runtime): The virtual machine component of Microsoft’s .NET framework. It manages the execution of .NET programs, providing services like just-in-time compilation, memory management, and security.

• Applications of C#:
  • Desktop applications, especially Windows apps
  • Web development using ASP.NET MVC framework

ASP.NET MVC Framework: A web application framework from Microsoft for building web applications using the Model-View-Controller (MVC) architectural pattern. It is part of the .NET framework and commonly used with C#.

*   Gaming with Unity game engine
*   Mobile apps using Xamarin

• Microsoft’s Visual Studio IDE is a primary development environment for C#.

Go (Golang): Performance and Scalability from Google

Go, also known as Golang, is an open-source language supported by Google.

• Compiled and statically typed, known for speed and scalability.
• Features a robust standard library.

Standard Library: A collection of pre-built modules, functions, and classes that are included with a programming language distribution. It provides common functionalities and tools that developers can readily use in their programs, reducing development time and effort.

• Inspired by C (static typing, runtime efficiency), Python, and JavaScript (readability, usability).
• Often does not require external web development frameworks due to its extensive standard library for tasks like creating REST APIs.
• Used for:
  • Back-end APIs and microservices
  • Distributed network services
  • Cloud-native development
• Companies using Go include Google, Uber, and Dropbox.

Python: Versatility and Readability

Python is a highly popular, dynamically typed, interpreted language.

• Also referred to as a scripting language.
• Compiled to bytecode before interpretation.
• Favored in various domains:
  • Machine learning and Artificial Intelligence (AI)
  • Data science
  • Automation
  • Web development (frameworks like Django and Flask)
• Python syntax differs from C-style languages (C, Java, JavaScript).
  • Uses indentation instead of curly braces and semicolons.

Indentation: The practice of using spaces or tabs to create visual structure in code, particularly in languages like Python. Indentation is not just for readability but is part of the syntax, defining code blocks and scope.

• Syntax resembles plain English.
• Companies using Python include NASA, Intel, IBM, and Spotify.

Ruby: Elegant and Rapid Development

Ruby is a portable, dynamically typed, interpreted language.

• Similar to Python in many ways: interpreted, compiled to bytecode, high-level, relatively easy to learn.
• Ruby is generally slower than Python.
• Also uses indentation syntax (no curly braces).
• Created with a focus on being a “pretty” and readable language.
• Applications include:
  • Desktop applications
  • Automation tools
  • Web development, primarily with Ruby on Rails.

Ruby on Rails: A popular web application framework written in Ruby. It follows the Model-View-Controller (MVC) architectural pattern and emphasizes convention over configuration, facilitating rapid development.

*   Rails is an **opinionated framework** with many built-in tools for rapid development.

Opinionated Framework: In web development, a framework that imposes specific conventions, structures, and ways of doing things. It guides developers to follow a certain path, often leading to faster development and more consistent applications, but with less flexibility.

*   Excellent for quickly creating **CRUD applications**.

CRUD Application: An acronym that stands for Create, Read, Update, and Delete. It refers to applications that implement these four basic operations for managing data, which are fundamental to many web applications.

*   **Scaffolding** features in Rails allow for very rapid creation of database-backed applications.

Scaffolding: A rapid prototyping technique in web frameworks that automatically generates basic code structures and functionalities for common application components, such as models, views, and controllers, often based on database schemas.

*   Rails has seen some decline in popularity but remains a powerful framework.
*   Companies using Ruby include Twitter, Dribbble, and Groupon.

JavaScript: The Language of the Web

JavaScript is the dominant language for web browsers.

• Initially used for interactive web page widgets.
• Evolved significantly with front-end frameworks like React, enabling complex single-page applications (SPAs).

Single-Page Application (SPA): A web application that loads a single HTML page and dynamically updates content as the user interacts with it, without requiring full page reloads. This provides a more fluid and app-like user experience.

• Node.js allows JavaScript to run on servers, expanding its use to back-end development.

Node.js: A runtime environment that allows JavaScript code to be executed on the server-side, outside of a web browser. It enables full-stack JavaScript development, using JavaScript for both front-end and back-end.

*   **npm (Node Package Manager)** provides a vast ecosystem of JavaScript packages.

npm (Node Package Manager): The default package manager for Node.js. It is used to install, manage, and share JavaScript packages (libraries and tools) for Node.js projects.

• Many full-stack developers prefer Node.js for back-end development for language consistency across front-end and back-end.
• Node.js is known for its speed in many tasks.
• JavaScript is an interpreted scripting language, dynamically typed by default.
• TypeScript, a superset of JavaScript, adds static typing.

Superset: In programming languages, a language A is a superset of language B if it includes all features of B and adds additional features. TypeScript is a superset of JavaScript, adding static typing.

• JavaScript is used virtually universally for front-end web development.
• Node.js is used in back-end development by companies like NASA, PayPal, Medium, and Netflix.
• JavaScript frameworks like React Native enable mobile app development.
• Frameworks like Electron allow JavaScript for desktop application development (e.g., VS Code, Postman, Slack).
• JavaScript’s ubiquity makes it a highly valuable skill.

PHP: Web Development Workhorse

PHP was an early popular language for web development.

• Dynamically typed scripting language for static and dynamic websites and web applications.
• Unique feature: PHP code can be embedded directly within HTML.
• Can be used procedurally or object-oriented (object-oriented is often preferred for cleaner code).
• Web frameworks like Laravel and Content Management Systems (CMS) like WordPress are built with PHP.

CMS (Content Management System): A software application that enables users to create, manage, and modify content on a website without needing extensive technical knowledge. WordPress, Drupal, and Joomla are popular examples.

• PHP is known for rapid development, making it popular for freelancing and small businesses.
• PHP has faced some criticism, but modern versions (PHP 8+) are improving.
• Often favored for quickly building and deploying web products.

Swift: Apple’s Ecosystem Language

Swift is a general-purpose compiled language developed by Apple.

• Primarily used for applications within the Apple ecosystem: iOS, iPadOS, macOS, etc.
• Considered relatively easy to learn and very fast.
• Replaced Objective-C as the primary language for iOS and macOS app development.
• Apple claims Swift is significantly faster than Objective-C.
• Compiled to Swift Intermediate Language then to machine code.
• Companies using Swift include Uber, Robinhood, and Lyft.

Conclusion

This overview covers some of the most popular programming languages. Each language has its strengths and is suited for different purposes. When choosing a language, consider your goals and the type of projects you want to work on. Experimenting with different languages, even briefly, can broaden your understanding and make learning subsequent languages easier. Familiarity with core concepts like high-level vs. low-level, static vs. dynamic typing, and compiled vs. interpreted languages provides a solid foundation for navigating the diverse world of programming.