Programming Logic & Design – Rapid-Review Notes

Program & Programming

• A program is a set of instructions that directs a computer to perform specific tasks such as:
  • display messages, receive user input, perform arithmetic, compare values, iterate
• Programming is the process (art + science) of planning, designing, and writing those instructions to solve a problem

Programming Language & Its Components

• Programming language: artificial language enabling human–computer communication
• Defined by two core components:
  • Syntax – rules governing form (symbols, punctuation, keywords)
  • Semantics – rules governing meaning (what each instruction does)

Classification of Programming Languages

• Two main generations:
  • Low-Level Language (machine dependent, minimal abstraction)
  • High-Level Language (hardware independent, human-readable)

Low-Level Language

• Types:
  • Machine Language – binary codes $1$/$0$
  • Assembly Language – mnemonics translated by an assembler
• Advantages: very fast execution, small memory footprint, high security
• Disadvantages: hard to code, debug, maintain; not portable

High-Level Language

• Paradigms:
  • Procedural – sequence of steps (e.g., C, BASIC)
  • Object-Oriented / Event-Driven – interactions among objects (e.g., C++, Java, C#)
• Advantages: easy to learn (English-like), portable, easier maintenance/debugging
• Disadvantages: slower execution, larger memory due to translation (compiler/interpreter)

Program Development Process

• Planning – define problem, goals, tasks
• Coding – write source code using an IDE/editor
• Testing & Debugging – locate and fix “bugs” until error-free
• Documentation – prepare user & technical references (description, hardware, OS, specs)
• Maintenance – update, enhance, and keep program running smoothly

Key Historical Milestones (Timeline)

• $1840s$ – Ada Lovelace writes first algorithm for Babbage’s Analytical Engine
• $1949$ – Assembly Language introduced (low-level symbolic code)
• $1952$ – Autocode (first compiled language, forerunner of COBOL & FORTRAN)
• $1957$ – FORTRAN developed for scientific computing; later used by NASA
• $1958$ – ALGOL introduces code blocks and nested functions; ancestor of C/C++/Java
• $1959$ – COBOL targets business applications; dominated enterprise computing
• $1964$ – BASIC designed for beginners; evolves into Visual Basic
• $1972$ – C language created; foundation for many modern languages

Quick Comparison Cheat-Sheet

• Low-Level ⇒ fast, compact, hardware-specific
• High-Level ⇒ readable, portable, slower
• Syntax ⇒ how code looks
• Semantics ⇒ what code means
• Development Steps ⇒ Plan → Code → Test/Debug → Document → Maintain