Basics of Programming

Basics of Programming

• A computer program is a sequential set of instructions in a computer language for performing specific tasks.
• Types of software include system software, web browsers, utility software, multimedia software, and spreadsheet software.
• Instructions must be executed in sequence unless otherwise directed.

Programming

• Programming combines art and science to instruct computers using programming languages.
• Codes written in these languages enable problem-solving, software applications, web development, data analysis, and process automation.
• Proficiency in programming opens career paths in software development, web development, data science, and artificial intelligence.
• Enhances critical thinking, logical reasoning, and problem-solving skills.

Evolution and History of Programming

• Initial programming involved machine code with binary instructions (0s and 1s) for direct hardware communication.
• Development of high-level programming languages simplified coding with human-readable syntax.
• Numerous programming languages and tools exist today catering to various paradigms and applications.

Programming Paradigms

• Procedural Programming: Organizes code into reusable procedures; examples include BASIC, C, C++, and Java.
• Object-Oriented Programming (OOP): Focuses on objects containing data and behaviors; examples include Python, VB.NET, and C#.
• Functional Programming: Emphasizes computation as mathematical function evaluation; prioritizes consistency and avoiding side effects.

Programming Languages

• Classified into low-level and high-level languages:
  • Low-level Language: Closer to machine code, allows detailed control over hardware; examples include assembly language and machine language.
  • High-level Language: Easier for humans to read and write; examples include C++, Pascal, PHP, Python, and Java.
• Selection of a programming language depends on project requirements, performance needs, and available community support.

Other Programming Terminologies

• Syntax: Rules that define valid statements in a programming language.
• Command: Specific instructions for tasks (e.g., "print" for displaying text).
• Integrated Development Environment (IDE): Software for code formatting, syntax checking, and testing, sometimes language-specific.
• Library: A collection of resources (objects/functions) pre-installed in an IDE.

Algorithm Representation

• Algorithms can be represented in pseudocode or flowcharts:
  • Pseudocode: Describes steps in an algorithm using natural language; uses common symbols for operations and keywords like PRINT, READ, SET.
  • Flowchart: Diagrammatic representation of algorithm steps; categorized into program flowcharts (illustrating software processes) and system flowcharts (showing data flow and systems interaction).

Flowchart Symbols

• Terminal: Marks the start and end of a process.
• Input/Output: Represents any input or output operation.
• Computer Processing: Illustrates processing performed by the computer system.
• Predefined Processing: Indicates processes not specifically defined.
• Comment: Clarifies or explains specific statements.
• Flow Line: Connects symbols showing process flow.
• Document Input/Output: Indicates document-related input/output.
• Decision: Marks points requiring decision-making.
• On-page Connector: Connects parts of flowchart on the same page.
• Off-page Connector: Links flowchart parts across separate pages.

Introduction to Java

• Java, created by Sun Microsystems in 1995, is a dynamic, high-level programming language used for web applications, mobile applications, enterprise software, big data, and server-side technologies.
• Utilized in game development, cloud computing, artificial intelligence (AI), and the Internet of Things (IoT).
• Based on the "Write Once, Run Anywhere" (WORA) philosophy, allowing Java code to run on any platform without modification.

Java Runtime Environment (JRE)

• JRE is essential for running Java programs, providing necessary class libraries and resources.
• Benefits of Java include:
  • Active Community Support ensuring a wealth of assistance for developers.
  • High-Quality Learning Resources available through documentation, books, and courses.
  • Extensive inbuilt functions and libraries reducing the need for writing code from scratch.
  • Strong security features to run untrusted code in a safe environment.

Java Virtual Machine (JVM)

• JVM serves as a runtime engine, executing Java applications.
• Combines features of both compilers (translating entire source code into machine language) and interpreters (executing code line by line).
• Converts Java bytecode into machine language for execution; .java files store source code.

Java APIs

• APIs are bundled software components that enhance functionality by integrating pre-written Java programs.
• Java language has around 50 keywords while Java API contains thousands of classes and methods available for use.

Java Skeleton Program Structure

• A simple Java program example prints “First Java Application”:

  class Skeleton {
     public static void main (String[] args) {
        System.out.println("First Java Application"); //for display
     }
  }
  

• Class serves as a blueprint for objects; the class name must be a valid identifier with specific naming rules.
• Java keywords define access modifiers (e.g., public, static, void) and the main method serves as the entry point for execution.

Identifiers and Reserved Words

• Identifiers must start with a letter, underscore, or dollar sign, contain no spaces, and are case-sensitive.
• Reserved words in Java cannot be used as identifiers; includes keywords like abstract, boolean, for, return, class, etc.

Code Blocks and Comments

• Code is organized within braces that define blocks; matching opening and closing braces are required.
• Comments improve code readability and can be single-line (//) or multi-line (/.../).

Saving, Compiling, and Executing a Program

• Java Development Kit (JDK) provides tools for developing and executing Java applications.
• Steps to save, compile, and run a Java program include:
  • Writing code in a text editor.
  • Saving the file with the correct .java extension.
  • Changing directories to the Java file location in command prompt.
  • Setting the JDK path to locate the Java compiler.
  • Compiling with javac [filename].java and executing with java [filename].

Practical Example

• A simple program structure is expressed as:

  public class Demo {
     public static void main (String a []) {
        System.out.println("First program in Java");
     }
  }
  

• Ensure the file is saved correctly to avoid automatic .txt extension.

Conclusion

• Understanding the Java environment and its components—JRE, JVM, APIs—is essential for effective programming.
• The program structure and syntax are critical for writing functional Java applications.

Explore the foundational concepts of programming, including the different types of software, programming languages, and the evolution of coding. This quiz covers the sequential nature of programming instructions and the impact of programming on various career paths and skills. Test your knowledge on how programming combines art and science.