Programming Languages Cheat Sheet

Programming Language Paradigms

Paradigm	Description	Characteristics	Examples
Imperative	Specify how to solve a problem using statements that change program state	Variables, assignment, control flow, subroutines	C, Pascal, Fortran, Basic
Object-Oriented	Structure programs around objects that contain data and methods	Encapsulation, inheritance, polymorphism, abstraction	Java, C++, C#, Python
Functional	Treat computation as evaluation of mathematical functions	Immutability, higher-order functions, recursion	Haskell, Lisp, ML, F#, JavaScript
Logic	Express programs as relations and use logical inference	Declarative, predicates, rules, facts	Prolog, Datalog
Procedural	Based on procedure calls and structured programming	Functions, procedures, variables, loops	Pascal, C, Fortran
Event-Driven	Program flow determined by events	Event handlers, callbacks, asynchronous execution	JavaScript, Visual Basic, C#

Type Systems

Concept	Description	Examples	Advantages/Disadvantages
Static Typing	Types checked at compile time	Java, C, C++, Haskell	Early error detection, performance, but less flexibility
Dynamic Typing	Types checked at runtime	Python, Ruby, JavaScript, PHP	Flexibility, rapid development, but runtime errors possible
Strong Typing	Strict enforcement of type rules	Haskell, Python, Java	Prevents type errors, but may require explicit conversions
Weak Typing	Loose enforcement of type rules	C, C++, JavaScript	Flexibility, but potential for errors
Polymorphism	Same interface for different data types	Function overloading, generics, inheritance	Code reusability, but complexity
Type Inference	Compiler deduces types automatically	Haskell, ML, Scala, C#	Less verbose, but harder to debug type errors

Memory Management

Approach	Description	Examples	Advantages/Disadvantages
Manual Management	Programmer explicitly allocates/deallocates memory	C, C++	Full control, performance, but memory leaks possible
Automatic (Garbage Collection)	Runtime system automatically reclaims unused memory	Java, C#, Python, JavaScript	No memory leaks, but performance overhead
Reference Counting	Track number of references to each object	Python (partially), Objective-C	Deterministic deallocation, but cycle detection issues
Borrowing/Rust Model	Compile-time ownership checking	Rust	No garbage collection, memory safety
Stack Allocation	Automatic allocation/deallocation in LIFO order	All languages	Fast allocation, automatic cleanup
Heap Allocation	Dynamic allocation with manual or automatic management	Most languages	Flexible lifetime, but slower allocation

Scoping Rules

Scoping Type	Description	Examples	Characteristics
Lexical (Static)	Variable scope determined by source code structure	C, Java, Python, C++	Predictable, checked at compile time
Dynamic	Variable scope determined at runtime	Early Lisp, Perl (special variables)	Flexible, but harder to debug
Global Scope	Variable accessible throughout program	All languages	Easy access, but can cause naming conflicts
Local Scope	Variable accessible only within specific block	All languages	Encapsulation, avoids naming conflicts
Block Scope	Variable accessible within a block	C, Java, JavaScript	Fine-grained control
Function Scope	Variable accessible within function	JavaScript (var)	Hoisting behavior

Programming Language Constructs

Construct	Purpose	Examples	Implementation
Control Structures	Control flow of execution	if/else, while, for, switch	Conditional jumps, loops in machine code
Functions/Methods	Modularize code into reusable units	function, procedure, method, subroutine	Stack frames, parameter passing, return mechanisms
Data Structures	Organize and store data	Arrays, records, classes, structs	Memory layout, access methods
Abstraction	Hide implementation details	Classes, modules, interfaces	Encapsulation, information hiding
Error Handling	Deal with exceptional conditions	try/catch/finally, exceptions, error codes	Stack unwinding, exception handling mechanism
Concurrency	Execute multiple tasks simultaneously	Threads, coroutines, async/await	OS threads, event loops, green threads

Compilation Process

Phase	Description	Input	Output
Lexical Analysis	Convert source code to tokens	Character stream	Token stream
Syntax Analysis	Parse tokens into syntax tree	Token stream	Parse tree/AST
Semantic Analysis	Check semantic rules	Parse tree	Decorated AST
Intermediate Code Generation	Create intermediate representation	Decorated AST	IR code
Optimization	Improve code efficiency	IR code	Optimized IR
Code Generation	Create target machine code	Optimized IR	Assembly/machine code
Assembly	Convert assembly to machine code	Assembly code	Object code
Linking	Combine object files	Object files, libraries	Executable

Language Implementation

Method	Description	Examples	Advantages/Disadvantages
Compilation	Translate entire program before execution	C, C++, Go, Rust	Fast execution, but longer development cycle
Interpretation	Execute program directly without prior translation	Python, Ruby, JavaScript (initially)	Fast startup, interactive development
Hybrid (Bytecode)	Compile to intermediate code, then interpret	Java (JVM), Python (.pyc), C# (.NET)	Platform independence, good performance
Just-In-Time (JIT)	Compile code at runtime	Java (HotSpot), JavaScript (V8), .NET	Optimization opportunities, but warm-up time
Transpilation	Translate source to source	TypeScript → JavaScript, CoffeeScript → JavaScript	Use advanced features on existing platforms

Language Features Comparison

Feature	C	Java	Python	JavaScript
Typing	Static, weak	Static, strong	Dynamic, strong	Dynamic, weak
Memory Management	Manual	Garbage collected	Garbage collected	Garbage collected
Paradigm	Procedural	OOP, imperative	Multi-paradigm	Multi-paradigm
Execution	Compiled	Bytecode + JIT	Interpreted	Interpreted + JIT
Concurrency	Threads, POSIX	Threads, async	Threads, async, GIL	Event loop, async
Platform	Cross-platform	Write once, run anywhere	Cross-platform	Browser, server

Standard Language Components

Component	Purpose	Examples	Implementation
Standard Library	Provide common functionality	String handling, I/O, data structures	Built-in functions, classes, modules
Runtime System	Support program execution	Memory manager, garbage collector	System libraries, kernel interfaces
Package Manager	Manage dependencies and libraries	npm, pip, Maven, Cargo	Repository systems, dependency resolution
Development Tools	Support development process	IDEs, debuggers, profilers	Language-specific tools
Documentation	Explain language features	API docs, tutorials, specifications	Automated doc generation

Language Design Principles

Principle	Description	Application	Benefits
Simplicity	Keep language features minimal and clear	Avoid unnecessary complexity	Easier to learn, implement, and maintain
Orthogonality	Combine features in consistent ways	Independent language constructs	Predictable behavior, fewer special cases
Generality	Use few constructs for many purposes	Polymorphism, generic types	Reduced redundancy, increased flexibility
Uniformity	Consistent syntax and semantics	Consistent naming, syntax rules	Easier to learn and use
Abstraction	Hide complexity behind simple interfaces	Functions, classes, modules	Manageable complexity, code reuse
Efficiency	Enable performance optimization	Low-level access, optimization opportunities	Fast execution, resource utilization