Basics of Programming and Algorithm Design

Fundamentals of Computer Programming

• Computer Program: A sequential set of instructions, known as codes, written or "programmed" in a computer language to let the computer perform a specific computation task.
• Execution Principle: Instructions in a computer program must be performed sequentially unless explicitly directed otherwise. Each instruction expresses a unit of work that a computer language can support.
• Software Examples:
  • System software
  • Web browsers
  • Utility software
  • Multimedia software
  • Spreadsheet software
• Computer / Programming Language: A set of grammatical rules that commands a computer or a device to behave in a specific way.
• Programming: The art and science of instructing computers to perform tasks using a specific programming language. It creates codes that tell a computer how to solve problems and accomplish various operations.
• Applications of Programming:
  • Developing computer programs and software applications
  • Designing websites
  • Analyzing data
  • Automating processes
• Career Opportunities: Software development, web development, data science, and artificial intelligence.
• Cognitive Benefits: Enhances critical thinking, logical reasoning, and problem-solving abilities, enabling programmers to break down complex tasks into manageable steps and develop efficient algorithms.

Evolution and History of Programming

• Initial Stage: Programming originally involved writing machine code consisting of binary instructions ($0$ and $1$) directly communicating with the computer's hardware.
• Development of High-Level Languages: As technology progressed, high-level programming languages were developed to simplify the coding process by utilizing human-readable syntax.
• Modern Ecosystem: A broad ecosystem of programming languages and tools exists to cater to different programming paradigms and application domains.

Programming Paradigms

• Definition: Conceptual frameworks and approaches to structuring and organizing code to solve problems and design software (synonymous with "pattern").
• Procedural Programming (Imperative Programming):
  • Focuses on organizing code into reusable procedures or functions.
  • Emphasizes the sequence of steps required to execute a program.
  • Examples: BASIC, C, C++, Pascal, Java.
• Object-Oriented Programming (OOP):
  • Revolves around objects that encapsulate data and behavior.
  • Promotes modularity, code reusability, and scalability.
  • Examples: Python, VB.NET, C#.
• Functional Programming:
  • Treats computation as evaluating mathematical functions.
  • Emphasizes consistency and avoids side effects.
• Selection Criteria: Choosing a paradigm depends on project nature, requirements, and desired programming style.

Classification of Programming Languages

• Low-Level Languages:
  • Close to machine code and hardware in syntax.
  • Provides direct control over hardware and resources, enabling fine-detailed coding.
  • Used for tasks requiring precise control and efficient execution.
  • Assembly Language: Uses specific instructions to control computer hardware.
  • Machine Language: All instructions are written strictly as binary numbers ($0$ and $1$).
• High-Level Languages:
  • Designed to be easy for humans to read, write, and understand.
  • Enables programming without specific knowledge of the processor or hardware on which the program runs.
  • Examples: C++, Pascal, PHP, Python, Java.
• Selection Criteria: Language choice depends on project requirements, performance needs, community support, and available libraries or frameworks.

Core Programming Terminologies

• Syntax: A set of rules defining combinations and arrangements of symbols or characters to create a valid statement in a language.
• Command: A unique instruction given to a computer application to perform a specific task or function (e.g., "print" to display text on screen).
• Integrated Development Environment (IDE): A software application for formatting code, checking syntax, and running and testing code. IDEs can support single or multiple programming languages.
• Library: A pre-built or installed collection of useful resources (such as objects and functions) within an IDE that can be used individually and configured to work together.
• Interpreter: A program that directly executes instructions written in a high-level language without converting them into machine language.
• Assembler: A program that converts instructions written in low-level assembly code into relocatable machine language.
• Compiler: A program that converts high-level languages into machine-readable code that a computer can execute.

Algorithms

• Definition: A set of steps that generates a finite sequence of simple computational operations leading to the solution of a given problem. It must be expressed in a natural language (e.g., English) that anyone can follow.
• Steps in the Programming Problem-Solving Process:
  1. Problem Analysis: Evaluating and outlining the problem and its solution requirements.
  2. Algorithm Design: Designing an algorithm to solve the problem.
  3. Coding: Implementing the algorithm in a programming language.
  4. Execution: Verifying whether the algorithm works or not.
• Algorithmic Example (Rectangle Volume):
  • Problem: Find and display the volume of a rectangle given its length, width, and height.
  • Required Formula: $\text{volume} = \text{length} \times \text{width} \times \text{height}$
  • Step-by-step Algorithm:
  1. Get the length of the rectangle
  2. Get the width of the rectangle
  3. Get the height of the rectangle
  4. Find the volume using the formula: $\text{volume} = \text{length} \times \text{width} \times \text{height}$
  5. Display the computed volume
• Algorithm Representation Tools: Pseudocode and Flowchart.

Pseudocode

• Definition: A technique used to describe distinct steps of an algorithm in a format that is simple to understand for anyone with basic programming knowledge.
• Standard Symbols & Operations:
  • Arithmetic operations: $+$, $-$, $*$, $/$
  • Assignment: $=$
  • Comparison: $==$, $\neq$, $<$; $>$
  • Relational bounds: $\le$, $\ge$
  • Logical operations: AND, OR
• Command Keywords: PRINT, WRITE, READ, SET, GO TO
• Formatting: Indentation is used to indicate branches and loops of instructions.
• Pseudocode Example (Rectangle Volume):
  • READ length
  • READ width
  • READ height
  • SET volume to 0
  • COMPUTE volume as length * width * height
  • PRINT volume

Flowcharts

• Definition: A diagrammatic or pictorial representation of the steps of an algorithm, serving as an easily understood substitute for textual descriptions.
• Categories of Flowcharts:
  • Program Flowcharts: Illustrate logical steps in a software program or programming task to understand a process, workflow, or algorithm. They contain steps to solve a problem unit for a specific result.
  • System Flowcharts: Show how parts of a system work together by displaying data flow and how decisions affect surrounding events.
• Standard Program Flowchart Symbols:
  • Terminal: Shows the start and end of a set of computer-related processes.
  • Input/Output: Shows any input or output operation.
  • Computer Processing: Shows any processing performed by a computer system.
  • Predefined Processing: Indicates any process not specially defined in the flowchart.
  • Comment: Used for writing any explanatory statement required to clarify something.
  • Flow line: Used for connecting symbols to indicate direction of flow.
  • Document Input/Output: Used when input comes from a document and output goes to a document.
  • Decision: Shows any point in the process wherein a decision must be made to determine further action.
  • On-page Connector: Connects parts of a flowchart continued on the same page.
  • Off-page Connector: Connects parts of a flowchart continued to separate pages.
• Five (5) Rules for Creating Program Flowcharts:
  1. Only standard symbols should be used in program flowcharts.
  2. Program logic should only show flow from top to bottom and/or left to right.
  3. Each symbol should contain only one entry point and one exit point, except the decision symbol (known as the single rule).
  4. Operations shown within a symbol should be expressed independently of any programming language.
  5. All decision branches should be well-labeled.

Academic References

• Chaudhuri, A. (2020). Flowchart and algorithm basics: The art of programming. Mercury Learning and Information.
• DG Junior (2023). Basics of programming: A comprehensive guide for beginners. DG Junior.