Java OOPs and Basic Programs 🚀

This repository contains Java programs that demonstrate core Object-Oriented Programming (OOP) concepts along with a collection of basic utility programs for beginners. It is designed to provide hands-on examples for learning and revising Java fundamentals.

📂 Folder Structure

java-Oops/
└── java_new/
    └── src/
        └── com/
            └── java/
                ├── abstraction.java
                ├── encapsulation.java
                ├── inheritance.java
                ├── polymorphism.java
                ├── user_input.java
                └── programes.java

📘 Topics Covered

🔹 OOP Concepts

• ✅ Abstraction: Using abstract classes and/or interfaces
• ✅ Encapsulation: Using private fields and public getters/setters
• ✅ Inheritance: Demonstrating base and derived classes

Each file in this section demonstrates one of the four main Object-Oriented Programming principles using Java.

---

🧱 Abstraction (abstraction.java)

Demonstrates:

• Abstract classes and methods
• Real-world examples with:
  • animal class and subclasses lion and tiger
  • shape class and subclasses circle, Triangle
  • Bank class and subclasses SavingsAccount, CurrentAccount

Key Concepts:

• Abstract methods must be implemented by subclasses.
• You cannot instantiate abstract classes.

---

🔐 Encapsulation (encapsulation.java)

Demonstrates:

• Using private variables and public getters/setters for data hiding
• Examples:
  • person, BankAccount, Rectangle, Employee, Car, Student, and Circle_ classes

Key Concepts:

• Encapsulation protects internal data by exposing controlled access via getter and setter methods.
• Promotes modularity and maintainability.

---

🧬 Inheritance (inheritance.java)

Demonstrates:

• Single-level inheritance with classes father → childern
• Method overriding with Animal and Cat classes

Key Concepts:

• Subclasses inherit fields and methods from their parent classes.
• Overriding allows a subclass to provide a specific implementation of a method.

---

🔁 Polymorphism (polymorphism.java)

Demonstrates:

• Compile-time Polymorphism (Method Overloading) — not present directly but can be extended
• Run-time Polymorphism (Method Overriding) using:
  • Animalfamily → bird, cat_
  • shapes → circle_shape, rectangle

Key Concepts:

• Polymorphism allows the same method to behave differently depending on the object calling it.
• Enhances flexibility and reusability of code.

🔹 Utility & Practice Programs (in Programes.java)

• Coin toss simulation
• Leap year check
• Finding factors of a number
• Quotient and remainder
• Swapping numbers
• Even or odd check
• Vowel or consonant check
• Finding the largest among three numbers
• Printing squares (power of 2)
• Harmonic number series

🔹 Input Handling (in user_input.java)

The user_input.java file demonstrates usage of the Scanner class to take various types of user input and perform basic operations like:

• Name confirmation loop
• Sum and product of integers
• Rectangle area calculation
• Printing user profile (name, roll number, interest)
• Square of a number
• Concatenating strings
• Perimeter of a square
• Equality check among three numbers
• Condition checking using if-else
• Marks input with validation (max 100 per subject)
• Percentage calculation

▶️ How to Run the Programs

1. Clone the repo:

   git clone https://github.com/your-username/java-Oops.git

2. Navigate to the source folder:

   cd java-Oops/java_new/src

3. Compile and run a Java file:

   javac com/java/Programs.java
   java com.java.Programs

Make sure your terminal is in the src directory so the package paths resolve correctly.

🧠 Ideal For

• Java beginners learning OOP
• Students practicing for exams or interviews
• Quick revision of Java fundamentals through examples