Introduction to Java Programming

Overview

• Welcome to the course on Java
• The course is divided into two parts:
  1. Introduction to Programming
  2. Data Structures and Algorithms

Part 1: Introduction to Programming

• Topics covered will include:
  • What is code?
  • How coding is done?
  • Installing tools
  • Input/Output, Variables, and Data Types
• Plan to cover these topics in 12 classes over 12 days.

Communication with Computers

• Human Communication: Using languages like Hindi or English to give instructions.
• Computer Communication: Uses binary (0s and 1s) instead of English or Hindi.

Why Binary?

• Computers are electrical devices operating with current:
  • 1 represents high voltage (current passes through the circuit).
  • 0 represents low voltage (no current passes through the circuit).
• Binary representation for decimal numbers:
  • Decimal 0 -> Binary 0
  • Decimal 1 -> Binary 1
  • Decimal 2 -> Binary 10
  • Decimal 3 -> Binary 11
  • Decimal 4 -> Binary 100
  • etc.

High-Level Languages

• Purpose: To make it easy to write complex instructions.
• Java: High-level language we will use.
• Process: Write code in Java -> Compiler converts it to binary -> Computer executes it.

Example: Making Maggi

• Steps and instructions are similar to giving commands to a computer.
• Example steps:
  1. Start
  2. Gather ingredients (Maggi, Masala, Water, Pot)
  3. Cook Maggi
  4. Check if it's done; if not, cook more
  5. Stop and eat

Flowcharts and Pseudocode

• Flowcharts: Visual way to represent steps in a process.
• Pseudocode: Written representation of what the code will do, but in plain English.

Example: Summing Two Numbers

• Flowchart Steps:
  1. Start
  2. Input two numbers
  3. Calculate the sum
  4. Print the sum
  5. End
• Pseudocode Steps:
  1. Start
  2. Input two numbers
  3. Calculate sum = number1 + number2
  4. Print sum
  5. End

Installing Java Development Tools

• Java Development Kit (JDK): Contains tools needed to write and execute Java programs.
• Integrated Development Environment (IDE): Software to write and run code.
  • Examples: Visual Studio Code, IntelliJ IDEA, Eclipse
• Installation:
  • Download JDK and preferred IDE (e.g., Visual Studio Code)
  • Follow our tutorials for setup (available videos).

Writing and Running Your First Java Program

• Creating a Java File:
  • Create a new file in the IDE.
  • Write the Java code.
  • Save the file with a .java extension (e.g., FirstClass.java).
• Basic Java Program Structure:

  public class FirstClass {
      public static void main(String[] args) {
          System.out.println("Hello, World!");
      }
  }
  

• Running the Program:
  • Compile the code using the IDE.
  • Execute to see the output (e.g., Hello, World!).

Understanding the Compilation and Execution Process

• Compilation: Converts source code (.java) to bytecode (.class).
  • Compiler in JDK performs this.
• Execution: Java Virtual Machine (JVM) converts bytecode to native code for execution.

Concepts in Java

• Functions: Blocks of code for specific tasks.
  • Example: public static void main(String[] args)
• Classes: Containers for functions and variables.
  • Example: public class FirstClass

Final Notes and Next Steps

• Understand coding basics and the workflow in Java.
• Practice by setting up your environment and writing simple programs.
• Watch tutorials and videos for additional help in setup.
• Practical Tip: Regular practice is crucial for mastering coding skills.

Next class: More on Input/Output and Variables.