feat: Add AddOverloadDemo class demonstrating method overloading

WHAT the code does:
- Defines `AddOverloadDemo` with three overloaded `add()` methods:
  1. **No parameters** → adds hardcoded numbers (10 + 20) and prints result.
  2. **Two parameters** → returns sum of two integers.
  3. **Three parameters** → calculates sum of three integers and prints result.
- `main()` demonstrates calling all three variations.

WHY this matters:
- Showcases **method overloading** in Java — same method name, different parameter lists.
- Demonstrates flexibility in designing APIs with multiple usage options.
- Highlights both returning values and printing results.

HOW it works:
1. `obj.add()` → calls no-arg method → prints `"Sum (no parameters): 30"`.
2. `obj.add(15, 25)` → calls two-arg method → returns 40 → printed in main.
3. `obj.add(5, 10, 20)` → calls three-arg method → prints `"Sum (three parameters): 35"`.

Tips & gotchas:
- Overloading is determined at **compile time** (static polymorphism).
- Cannot overload methods by return type alone — parameter list must differ.
- Ensure method signatures are distinct enough to avoid ambiguity.
- Consistency matters: mixing printing vs returning can confuse API users.

Use-cases:
- Educational example for **compile-time polymorphism**.
- Practical for calculator-like utilities with multiple input forms.
- Foundation for designing libraries where methods accept variable arguments.
- Interview prep problem for method overloading.

Short key: class-add overload demo-method-overloading.

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

Author: Someshdiwan

Section10Methods/PracticeProblems/src/AddOverloadDemo.java

@@ -1,24 +1,22 @@
 public class AddOverloadDemo {
-
-    // Method 1: No parameters, adds hardcoded numbers
+    // Method 1: No parameters, adds hardcoded numbers.
     void add() {
         int a = 10, b = 20;
         int sum = a + b;
         System.out.println("Sum (no parameters): " + sum);
     }
 
-    // Method 2: Two parameters, returns the sum
+    // Method 2: Two parameters, returns the sum.
     int add(int x, int y) {
         return x + y;
     }
 
-    // Method 3: Three parameters, prints the sum
+    // Method 3: Three parameters, prints the sum.
     void add(int x, int y, int z) {
         int sum = x + y + z;
         System.out.println("Sum (three parameters): " + sum);
     }
 
-    // Main method to call all add methods
     public static void main(String[] args) {
         AddOverloadDemo obj = new AddOverloadDemo();