feat: Add ConstructorDemo1 with overloaded constructors for rectangles and squares

WHAT the code does:
Defines ConstructorDemo1 with private fields length and breadth.
Implements three constructors:
- Default constructor: sets length and breadth to 1.
- Parameterized constructor (double l, double b): initializes with given length and breadth.
- Square constructor (double s): sets both length and breadth to the same value.
Provides display() method to print length and breadth.
Defines Constructor with main():
- Demonstrates creation of objects using all three constructors.
- Calls display() to show initialized values.

WHY this matters:
Demonstrates constructor overloading in Java for flexible object initialization.
Encapsulates rectangle and square representation in a single class.
Illustrates default, parameterized, and convenience constructors.
Shows how constructors eliminate the need for repetitive setter calls after object creation.

HOW it works:
c1 = new ConstructorDemo1(); → length = 1, breadth = 1.
c2 = new ConstructorDemo1(5.0, 10.0); → length = 5, breadth = 10.
c3 = new ConstructorDemo1(7.0); → length = breadth = 7.
Each object calls display(), printing initialized values.

Tips and gotchas:
Field values are private, enforcing encapsulation; display() provides controlled access.
Constructors with similar signatures can create ambiguity; here, double vs (double,double) resolves clearly.
Adding validation inside constructors (e.g., rejecting negative dimensions) improves robustness.
Overriding toString() could replace display() for more idiomatic printing.

Use-cases:
Educational demonstration of constructor overloading in Java.
Practical design for representing rectangles and squares in geometry problems.
Foundation for extending into area, perimeter, or volume calculations.

Short key: class-constructordemo1 constructor-overloading rectangle-square.

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

Author: Someshdiwan

Section11ObjectOrientedProgramming/src/Constructor.java

@@ -1,44 +1,38 @@
-class ConstructorDemo1
-{
+class ConstructorDemo1 {
     private double length;
     private double breadth;
 
-    public ConstructorDemo1()
-    {
+    public ConstructorDemo1() {
         length=1;
         breadth=1;
     }
-    public ConstructorDemo1(double l, double b)
-    {
+    public ConstructorDemo1(double l, double b) {
         length=l;
         breadth=b;
     }
-    public ConstructorDemo1(double s)
-    {
+    public ConstructorDemo1(double s) {
         length=breadth=s;
     }
+
     // Method to display the values
-    public void display()
-    {
+    public void display() {
         System.out.println("Length: " + length + ", Breadth: " + breadth);
     }
 }
 
-public class Constructor
-{
-    public static void main(String[] args)
-    {
+public class Constructor {
+    public static void main(String[] args) {
         ConstructorDemo1 c = new ConstructorDemo1();
 
         // Calling different constructors
+        ConstructorDemo1 c1 = new ConstructorDemo1(); // Default constructor.
+
+        ConstructorDemo1 c2 = new ConstructorDemo1(5.0, 10.0); // Parameterized constructor.
 
-        ConstructorDemo1 c1 = new ConstructorDemo1(); // Default constructor
-        ConstructorDemo1 c2 = new ConstructorDemo1(5.0, 10.0); // Parameterized constructor
-        ConstructorDemo1 c3 = new ConstructorDemo1(7.0); // Square constructor
+        ConstructorDemo1 c3 = new ConstructorDemo1(7.0); // Square constructor.
 
-        // Displaying the values
         c1.display();
         c2.display();
         c3.display();
     }
-}
+}