feat: Demonstrate 2D array declaration, iteration, and various declaration syntaxes

🧠 Logic:
- Initializes a 3×3 array `B` with literal values and prints its elements using nested loops indexing rows and columns (`B.length` and `B[0].length`).
- Shows multiple ways to declare and initialize 2D arrays (`int[][] A`, `int[][] c`, `int[][] D`, `int[] E[]`, and combined declarations).
- Highlights declaration pitfalls with mixed dimensions in a single statement (e.g., `int[] M, F[]` vs. `int[] I, J, K, L`).
- Includes comments explaining how `B[0].length` provides the column count for iteration.

Signed-off-by: Somesh diwan <[email protected]>

Author: Someshdiwan

Section9ArrayAB/Array IMP/TwoDArray.java

@@ -1,10 +1,20 @@
 public class TwoDArray {
     public static void main(String[] args) {
-
         int B[][] = {{1, 2, 3}, {2, 4, 6}, {1, 3, 5}};
-        for (int i = 0; i < B.length; i++)
-        {
+
+        for (int i = 0; i < B.length; i++) {
             for (int j = 0; j < B[0].length; j++)
+           /*
+           Gives the number of columns (using the first row's length)
+           refers to the first row of the 2D array, which is `{1, 2, 3}`.
+           It's a 1D array itself. `B[0]`
+           So:
+            - = `{1, 2, 3}` `B[0]`
+            - = `3` (the number of columns in the first row) `B[0].length`
+
+            That's why in the loop condition is used to determine how many times to iterate through each column
+            - it gives us the width of the array (number of columns). `B[0].length`
+            */
             {
                 System.out.print(B[i][j] + " ");
             }
@@ -14,16 +24,14 @@ public static void main(String[] args) {
         int A[][] = new int[5][5];
 
         int c[][];
-
         c=new int[5][5];
 
-        int[][] D = new int[5][5];
-
+        int[][]D = new int[5][5];
         int[]E[]  = new int[5][5];
 
         int[]M,F[];
         M=new int[5]; //1D Array.
-        F=new int[5][5]; //Its Two D Array.
+        F=new int[5][5]; //It's Two D Array.
 
         int[]G, H[]; //2D Array
 
@@ -37,6 +45,6 @@ public static void main(String[] args) {
                 Key Points:
         int[] represents a 1D array.
         int[][] represents a 2D array.
-                Avoid mixing , and ; in a single declaration.*/
+                Avoid mixing, and; in a single declaration.*/
     }
-}
+}