Computer Programming: History and Basics

• The lecture introduces fundamental concepts in computer programming.
• It outlines learning objectives covering computer history, components, languages, and program development.

Brief History of a Computer

• The concept of the computer dates back to the 19th century with Charles Babbage.
• Early computers were developed to solve complex numerical problems.
• Modern smartphones have more computing power than early computers.

What is a Computer?

• A computer is an electronic device that operates under the control of stored instructions.
• Computers can accept data, process it, produce results, and store them.
• The information processing cycle consists of input, processing, output, and storage.

Categories of Computers

• Supercomputers are the most powerful type of computer.
• Mainframe computers are used by large organizations.
• Midrange computers serve medium-sized organizations.
• Microcomputers include personal computers.
• Mobile computers/devices include laptops and smartphones.
• Game consoles are designed for gaming.
• Embedded computers are integrated into other devices.

Components of a Computer

• Hardware includes the physical parts of a computer.
• Software includes the instructions that tell the computer what to do.
• The computer consists of hardware and software.

CPU (Central Processing Unit)

• The CPU fetches and decodes instructions.
• The control unit (CU) controls the flow of information and internal CPU operations.
• The program counter (PC) points to the next instruction.
• The instruction register (IR) holds the currently executing instruction.
• The arithmetic logic unit (ALU) performs arithmetic and logical operations.

Main Memory

• Main Memory is directly connected to the CPU.
• Programs must be loaded into main memory before they can be executed.
• Data must be in main memory to be manipulated.
• Data in main memory is lost when the computer is turned off.

Secondary Storage

• Secondary storage devices store information permanently.
• Examples include hard disks, floppy disks, zip disks, CD-ROMs, tapes, and flash drives.

Input/Output Devices

• Input devices feed data and programs into computers.
• Input devices include keyboards, mice, and secondary storage.
• Output devices display results.
• Output devices include monitors, printers, and secondary storage.

Program/Software

• Software/Programs are sets of instructions that perform specific tasks.
• System programs control the computer.
• Application programs perform specific tasks.
• Examples of application programs are word processors, spreadsheets, and games.

Programming

• Programming is the process of creating instructions for a computer to perform a task.
• Programming can be done using languages like JavaScript, Python, and C++.

Programming Language

• A programming language is a set of written words and symbols used to write programs.
• A programmer is a person who writes programs.

Overview of Programming Languages

• Machine language is the fundamental language computers use.
• Assembly language uses abbreviations for instructions.
• High-level languages, like Fortran and C, are more abstract.
• Very high-level languages are problem-oriented.
• Fifth-generation languages use natural language.

The Language of a Computer

• Machine language is a language of a computer and consists of binary code.
• A bit (binary digit) is a 0 or 1.
• A binary code is a sequence of 0s and 1s.
• A byte is a sequence of eight bits.

Coding Schemes

• ASCII is used for 128 characters.
• EBCDIC is used by IBM.
• Unicode is used for 65536 characters.

Relationship Between Compiler, Interpreters and Programs

• Programs must be converted to machine code.
• A language translator is needed to convert other languages to machine languages.

Language Translator

• A language translator is software that translates a program written in 2nd, 3rd, or higher-generation language into machine language.
• Assemblers translate assembly language to machine language.
• Compilers translate the entire source code into machine language before execution.
• Interpreters translate and execute code one statement at a time.
• Compilers generate object code, while interpreters do not.

Compiler

• A compiler converts the entire source program into machine language before executing it.

Interpreter

• An interpreter translates and executes one program code statement at a time.
• Interpreters do not produce an object program.

Why Computer Program is Important?

• Modern civilization relies on computer programs for operations.
• Software is essential to the products, services, and innovations that power the industrialized world.
• Computer programming is harnessed to use computing power efficiently and accurately.

Importance of Good Computer Program

• Good programs deliver functionality and perform well for the user.
• Good programs can be maintained, are dependable, and acceptable.
• Good programs are trusted by users for which it was designed.

Program Development Life Cycle

• The problem-solving phases are a series of steps programmers use to build computer programs.
• The steps are Analysis, Design, Implementation, Testing/Debugging, and Maintenance.

Programming Paradigm

• A programming paradigm represents a style or model for programming.
• The programming paradigm is a model for a class of programming languages that share a set of common characteristics and its differences.

Imperative paradigms

• Defines computation in terms of program state and statements that change the state.
• Computer languages are mostly based on an imperative style.
• Fortran, COBOL, and Pascal are examples

Object Oriented paradigms

• Imperative style with added data plus abstraction and encapsulation.
• Allows programmers to write reusable, extensible code.
• Abstraction, Encapsulation, and Inheritance are key features.
• Smalltalk and Java are examples.

Functional Paradigm

• Focuses on the definition of functions.
• Alternative paradigm for describing computation.
• Sometimes called the applicative language.
• Haskell, Miranda, LISP, and Scheme are examples.

Logic Paradigm

• Based on symbolic logic.
• Mathematical logic to computer programming.
• No need for control abstraction.
• Prolog is an example.