feat: Add ReturningValues class with add and product instance methods

WHAT the code does:
- Defines a `ReturningValues` class with attributes `number1` and `number2`.
- Constructor initializes both attributes.
- `addToNumbers(int a)` increases both numbers by a given value.
- `getProduct()` computes and returns the product of the two numbers.
- `main()` demonstrates:
  - Creating an object with values (1, 2).
  - Modifying them with `addToNumbers(3)` → numbers become (4, 5).
  - Printing updated values.
  - Calculating product (4 × 5 = 20) and printing result.

WHY this matters:
- Demonstrates **instance methods vs constructor initialization**.
- Shows **state mutation** of object attributes through methods.
- Introduces returning values from methods instead of only printing.

HOW it works:
1. Constructor assigns `1` and `2` to `number1` and `number2`.
2. `addToNumbers(3)` → adds 3 to each, making them `4` and `5`.
3. `getProduct()` → multiplies updated values → `20`.
4. Results are printed step by step.

Tips & gotchas:
- Fields are package-private (default) → better to make them `private` and use getters for encapsulation.
- Multiple calls to `addToNumbers()` keep incrementing values.
- Using `int` can overflow for very large numbers; `long` or `BigInteger` may be safer.
- `getProduct()` creates a local variable unnecessarily → can directly `return number1 * number2`.

Use-cases:
- Educational example for **methods returning values**.
- Foundation for designing classes that encapsulate arithmetic logic.
- Practice with constructors, instance fields, and mutator methods.
- Can be extended to more complex math operations.

Short key: class-returning values-add-product.

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

Author: Someshdiwan

Section10Methods/Methods 2.O/src/ReturningValues.java

@@ -1,39 +1,36 @@
-public class ReturningValues
-{
-    //Instance attributes//
+public class ReturningValues {
+    //Instance attributes
     int number1;
     int number2;
 
-    //Constructor//
-    public ReturningValues (int value1, int value2)
-    {
+    //Constructor
+    public ReturningValues (int value1, int value2) {
         number1 = value1;
         number2 = value2;
     }
 
-    //Instance Methods//
-    public void addToNumbers(int a)
-    {
+    //Instance Methods
+    public void addToNumbers(int a) {
         number1 += a;
         number2 += a;
     }
 
-    public int getProduct()
-    {
+    public int getProduct() {
         int product = number1 * number2;
         return  product;
     }
 
-    public static void main(String[] args)
-    {
-        //create the object with initial values
+    public static void main(String[] args) {
+        //create the object with initial values.
         ReturningValues exampleObject = new ReturningValues(1, 2);
-        //modify the values through a method
+
+        //modify the values through a method.
         exampleObject.addToNumbers(3);
         System.out.println(exampleObject.number1);
         System.out.println(exampleObject.number2);
-        //calculate some value through another method
+
+        //calculate some value through another method.
         int number3 = exampleObject.getProduct();
         System.out.println(number3);
     }
-}
+}