2D Arrays in Java

Introduction

• 2D arrays can be challenging for beginners.
• Used to store data in a table-like structure with rows and columns.
• Example application: Display screens (e.g., 1920x1080 pixels with RGB values).

Creating 2D Arrays

1. Direct Initialization:

   • Declare with int[][].
   • Initialize by listing elements in curly braces.
   • Example: int[][] lotteryCard = { {20, 15, 7}, {8, 7, 19}, {7, 13, 14} };
   • Represents a fixed 3x3 array.

2. Using 'new' Keyword:

   • Declare with dimensions first, then assign values.
   • Example: int[][] lotteryCard2 = new int[3][3]; lotteryCard2[0][0] = 20; lotteryCard2[0][1] = 15; // Continue assigning...
   • Provides flexibility but requires manual value assignment.

Accessing Elements

• Use array indexing: array[row][column].
• Example: lotteryCard[0][0] retrieves the value 20.

Printing Array Elements

1. Single Element:

   • Directly print using index.
   • Example: System.out.println(lotteryCard[0][0]); prints 20.

2. Using Loops for Multiple Elements:

   • For Loop:
     • Iterate over arrays to print elements.
     • Example to print a diagonal: for (int i = 0; i < 3; i++) { System.out.println(lotteryCard[i][i]); }
   • To print all elements: for (int i = 0; i < 3; i++) { for (int j = 0; j < 3; j++) { System.out.print(lotteryCard[i][j] + " "); } System.out.println(); }

Conclusion

• Understanding 2D arrays is crucial for representing tabular data.
• Practice with simple projects, such as a lottery ticket array.
• Engage with community discussions for better learning.

Additional Notes

• Further tutorials will cover advanced topics like for loops in detail.
• Encourage interaction and questions in the programming community.