Programming Languages

• Programming involves converting problem solutions into computer instructions.
• It includes developing and implementing instruction sets that enable computers to perform tasks.

History of Programming Languages

• 1st Generation: Machine Language

  • Instructions are entered in binary format (1s and 0s)
  • This made it tedious and error-prone
  • Programmers designed code by hand and transferred it via punch cards, punch tape, or switches.
  • Instructions executed directly by the CPU, were very fast
  • Memory management was manual
  • Programs were difficult to edit and debug.
  • It was used to code simple programs only

• 2nd Generation: Assembly Languages (Low Level)

  • Appeared in the 1950s
  • Human-readable source code improved on the first generation
  • Source code needs compilation/assembly into machine code before CPU execution
  • Logical structure and debugging were supported

• 3rd Generation: High-Level Languages

  • The primary languages used for general-purpose programming today
  • Languages vary widely in abstraction and syntax.
  • Share logical structure improvements over assembly languages.
  • Based on natural language.
  • Often designed around structured programming.
  • Examples include C, C++, C#, Java, Basic, COBOL, Lisp, and ML.

• 4th Generation Languages

  • High-level languages built around database systems, and used in commercial environments.
  • Improved abstraction and statement power over 3GLs reduces errors and programming effort
  • This ultimately lowers software development costs.
  • Designed for specific purposes, like querying databases (SQL) or creating reports (Oracle Reports)
  • More oriented towards problem-solving and systems engineering.
  • Examples: Progress 4GL, PL/SQL, Oracle Reports, Revolution language, SAS, SPSS, SQ.

• 5th Generation Languages

  • Improved previous generations by skipping algorithm writing, emphasizing constraints/conditions.
  • Designed to solve problems without requiring the programmer to specify an algorithm
  • Programmer inputs logical constraints
  • An AI-based compiler builds the program based on constraints.
  • Examples: Prolog, OPS5, Mercury

Programming Paradigms

• A paradigm is a standard, perspective, or way of looking at something.
• It is a fundamental approach for designing and implementing computer programs, providing principles, concepts, and techniques.
• Defines code structure, organization, and flow, including methodologies for problem-solving.
• Programming paradigms dictate structure and programmer's thought process.
• Different paradigms have strengths/weaknesses; the right choice impacts efficiency, maintainability, and scalability.

Types of Programming Paradigms

• Unstructured Programming

  • Statements are executed sequentially in the order written.
  • Uses "GoTo" statements to pass control to other program sections.
  • Understanding program logic requires execution.
  • Difficult to understand the logic.

• Structured Programming

  • Addresses challenges that unstructured programming can pose
  • Employs a top-down design model.
  • Developers break programs into subsections.
  • Functions are coded in separate modules that can be loaded into memory efficiently and reused.
  • Modules are integrated into the overall structure after individual testing.
  • Program flow uses hierarchical looping constructs ("for," "repeat," "while").
  • It discourages the use of "GoTo" statements.
  • Modules should not exceed 100 lines, ideally fitting one page or screen.
  • Examples include: C, Pascal, Fortran, Cobol.

• Object-Oriented Programming

  • Programs are written as a collection of classes and objects meant for communication.
  • The object is the smallest entity.
  • Computations are performed on objects.
  • It places more emphasis on data rather than procedure
  • Handles almost all kinds of real-life problems.
  • Examples include: Java, C, Python.

• Internet Based Programming

  • Programming is oriented to internet applications
  • PHP, ASP, Perl, JavaScript, HTML, Java, etc. are used

• Visual Programming

  • Uses visual representations like graphics, animation, or icons.
  • The language manipulates information, supports visual interaction, or allows programming with visual expressions.
  • Microsoft Visual Basic is a visual language derived from BASIC
  • It enables Rapid Application Development (RAD) for GUI applications.

Choosing a Programming Paradigm

• Choice depends on the problem domain, language capabilities, and personal preference.
• Many languages accommodate multiple paradigms, enabling programmers to blend approaches.