feat: Add ShapeVIMP abstract class with CircleVIMP and Rectangle implementations

WHAT the code does:
Defines abstract class ShapeVIMP with two abstract methods:
- peimeterIMP(): calculates perimeter.
- areaIMP(): calculates area.
Defines CircleVIMP extending ShapeVIMP:
- Implements peimeterIMP() as 2πr.
- Implements areaIMP() as πr².
Defines Rectangle extending ShapeVIMP:
- Implements peimeterIMP() as 2 × (length + breadth).
- Implements areaIMP() as length × breadth.
Defines AbstractIMP with main():
- Creates a Rectangle, sets length=10 and breadth=5.
- Assigns Rectangle to a ShapeVIMP reference.
- Calls areaIMP() via the abstract reference and prints the result (50.0).

WHY this matters:
Demonstrates **abstraction**: ShapeVIMP defines a contract for all shapes (area and perimeter).
Shows **polymorphism**: a ShapeVIMP reference can point to different shape objects (Rectangle, CircleVIMP).
Encourages code reuse and flexibility by separating "what a shape does" from "how each shape does it".

HOW it works:
ShapeVIMP s = r (where r is a Rectangle).
- Calls areaIMP() → resolves to Rectangle.areaIMP() → computes 10 × 5 = 50.
Same approach could be used for CircleVIMP by setting radiusIMP and calling its methods.

Tips and gotchas:
Method names should follow Java naming conventions (perimeter() instead of peimeterIMP()).
Fields (radiusIMP, length, breadth) should be private with constructors or setters for encapsulation.
Currently only Rectangle is demonstrated; adding a CircleVIMP demo in main would show polymorphism more clearly.
Abstract class ShapeVIMP could be refactored into an interface if only abstract methods are required.

Use-cases:
Educational example of abstract classes and polymorphism in OOP.
Foundation for building extensible geometry libraries.
Practical demonstration of how base contracts ensure consistency across different subclasses.

Short key: class-shapevimp circle rectangle abstract-polymorphism.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

Section13AbstractClasses/src/AbstractIMP.java

@@ -1,44 +1,37 @@
 import java.awt.*;
-abstract class ShapeVIMP
-{
+
+abstract class ShapeVIMP {
     abstract public double peimeterIMP();
     abstract public double areaIMP();
 }
 
-class CircleVIMP extends ShapeVIMP
-{
+class CircleVIMP extends ShapeVIMP {
     double radiusIMP;
 
-    public double peimeterIMP()
-    {
+    public double peimeterIMP() {
         return 2 * Math.PI * radiusIMP;
     }
 
-    public double areaIMP()
-    {
+    public double areaIMP() {
         return Math.PI*radiusIMP*radiusIMP;
     }
 }
 
-class Rectangle extends ShapeVIMP
-{
+class Rectangle extends ShapeVIMP {
     double length;
     double breadth;
 
-    public double peimeterIMP()
-    {
+    public double peimeterIMP() {
         return 2*(length+breadth);
     }
-    public double areaIMP()
-    {
+
+    public double areaIMP() {
         return length*breadth;
     }
 }
 
-class AbstractIMP
-{
-    public static void main(String[] args)
-    {
+class AbstractIMP {
+    public static void main(String[] args) {
         Rectangle r=new Rectangle();
         r.length=10;
         r.breadth=5;