The historical development of programming languages has gone through one stage after another, from machine language to high-level language, it is also closer to the way of human thinking, easy to write, good readability, and more efficient to develop.

  • Machine-oriented programming (MOP)
  • Procedure-oriented Programming (POP)
  • Object-oriented Programming (OOP)

Programming itself is engineering, not science. This means that all roads lead to Rome, and there is no one size fits all. So, in fact, many people argue about them by different aspects (e.g. coding style, performance, the difficulty of mastering), which language is the best, which framework is better, these are actually philosophical questions, because there is no unified standard answer.

Difficulty of Mastering

Different programming languages have some similarities in common, but also have their own uniqueness, they are all born to solve certain problems, no one language is absolutely good, and they all have their own philosophical ideas.


  • Ruby: Optimized for programmer happiness
  • Python: Beautiful is better than ugly
  • PHP: Quick and dirty
  • Java: Compile once, run everywhere


Dynamically Typed Language

A language that checks the type of data at runtime. Such languages do not assign a type to a variable, but get the data type when a value is assigned.


  • ECMAScript (JavaScript)
  • Python
  • Ruby
  • PHP
  • Erlang
  • VBScript
  • Swift
  • Perl

Statically Typed Language

Statically typed languages check the type at compile time before running. When writing code, each variable declared must specify the type.


  • C/C++
  • C#
  • Object-C
  • Java
  • Scala
  • Go

PS. Whether a language is dynamically typed or not is completely irrelevant to whether the language is typesafe, don’t tie them together.

Dynamic Programing Language

Dynamic languages (Dynamic Programming Languages) are a class of languages that can change their structure at runtime.


  • C#
  • Object-C
  • Python
  • PHP
  • Erlang
  • JavaScript

Static Programing Language

Static languages (Static Programming Languages) are languages whose structure cannot be changed at runtime.


  • C/C++
  • Java

Strongly Typed Language

Strongly typed means that the type of a value doesn’t change in unexpected ways. A string containing only digits doesn’t magically become a number, as may happen in Perl. Every change of type requires an explicit conversion.

E.g. 1 / 3 = 0, int / int = int


  • C/C++
  • C#
  • Object-C
  • Java
  • Python
  • Ruby
  • Go

Weakly (Loosely) Typed Language

Weakly typed languages are looser in checking variable types and tolerate implicit type conversions.


  • 1 / 3 = 0.33333..., int / int = float
  • 1 + "3" = 13, int / string = string


  • JavaScript
    • Duck Typing (i.e. looks like a duck, talks like a duck, it’s a duck)
  • PHP

Compiled Language

Compiled language means that a special compilation process is required before the program is executed, and the program source file is compiled into a file in machine language, which can be executed by the machine and has high execution efficiency.


  • C/C++
  • Object-C
  • Pascal
  • Swift

Interpreted Language

Interpreted language means that the source code does not need to be compiled in advance, at runtime, it must be interpreted before running.


  • JavaScript
  • Python
  • PHP
  • Perl
  • Ruby
  • Erlang
  • Java
  • C#

For Java and C#, it can be said to be a semi-compiled and semi-interpreted language. The source code needs to be converted into an intermediate file (bytecode file), and then the intermediate file is taken to the virtual machine for execution.


Data Types

  • Basic
    • Number
      • Byte
      • Short
      • Integer
      • Long
      • Float
      • Double
    • Character
    • String
    • Boolean
    • Null
    • Undefined
  • Collection
    • Linear
      • List
      • Linked list
      • Tuple
      • Queue
      • Stack
    • Non-linear
      • Map

Variable Lifecycle

  • Static
  • Dynamic

Basic Structure

In structured programming, a program is written with only 3 basic structure:

  • Sequences
  • Selections
  • Loops


  • Variadic function
  • Default value
  • Keyword arguments

Programming Paradigm

Functional Programming

  • Erlang
  • Scala

Structured or modular programming

  • C#
  • PHP

Imperative programming

This alternative to OOP focuses on function rather than models.

  • C++
  • Java

Declarative programming

This programming method involves statements on what the task or desired outcome is but not how to achieve it.

  • Prolog
  • Lisp

Logical programming

This programming method, which is based mostly in formal logic. It contains a set of sentences that express facts or rules about a problem domain. It focuses on tasks that can benefit from rule-based logical queries.

  • Prolog

Object-oriented Programming (OOP)


  • Encapsulation
  • Inheritance
    • Override (Type and quantity of parameters are the same)
    • Overload (Anyone of type and quantity of parameters is different)
  • Polymorphism

Accessibility (Access modifier):

  • Public
    • Access by any class
  • Protected
    • Access by subclass
  • Friendly
    • Access by friend’s class (e.g. the same package)
  • Private
    • Access by the class itself


  • Construction
  • Destruction

Programming Model

In programming, the way of abstraction, organization or reuse of code. The programming model is mainly methods and ideas.

  • Event-driven (Publish/Subscribe Model)
    • Basic
      • Don’t care about who is the receiver
    • Components
      • Event Queue
      • Event Mediator
      • Event Channel
      • Event Processor
    • Frameworks
      • select
      • poll
      • epoll
      • libev
      • interrupt system
  • Message-driven
    • Basic
      • Care about who is the receiver
    • Framework
      • API Gateway
      • gRPC
      • Micro-service Architect
  • Data-driven





Exception Handle



Asynchronous Programming

  • .NET: delegate
  • Java:
    • Anonymous inner class
    • Closure (Java 7)
  • C++
    • tr1::function/bind (C++0X)

Generics Programming

Garbage Collection (GC)

Higher-order Function (HOF)

Dynamic Type conversion

Meta Programming

  • Introspection
    • JAVA: Reflection

Serialization & Deserialization

Language Characteristics

  • Ruby
    • Block
    • Range
    • Symbols
  • Java
    • Dynamic Proxy
  • C#
    • LINQ
    • Extension Method

How to choose a language?

  • Whether the developer is familiar with a language.
  • Which language provides more powerful features that can be applied to the current project.
  • Focus on robustness or flexibility and expressiveness.
  • Whether there are tools to improve development efficiency, such as peripheral frameworks (libraries), etc.