Java Jagged Arrays

What is a Jagged Array?

A jagged array is an array of arrays where member arrays can be of different sizes. This allows for more flexible memory allocation.

Example:

int[][] arr = { {1, 2}, {3, 4, 5, 6}, {7, 8, 9} };

Here, the number of columns in each row is different.

Declaration and Initialization

int[][] jaggedArray = new int[3][];  // Declaring a jagged array with 3 rows
jaggedArray[0] = new int[2];  // 2 columns in the first row
jaggedArray[1] = new int[4];  // 4 columns in the second row
jaggedArray[2] = new int[3];  // 3 columns in the third row

Alternative Ways to Initialize

int[][] arr = { 
    new int[] {10, 20, 30 ,40},
    new int[] {50, 60, 70, 80, 90, 100},
    new int[] {110, 120}
};

Looping Through a Jagged Array

int[][] arr = { {1, 2}, {3, 4, 5, 6}, {7, 8, 9} };
for (int i = 0; i < arr.length; i++) {
    for (int j = 0; j < arr[i].length; j++) {
        System.out.print(arr[i][j] + " ");
    }
    System.out.println(); // for adding a new-line
}

Advantages of Jagged Arrays

• Dynamic Allocation: Allows memory allocation at runtime.
• Space Utilization: Saves memory when different row sizes are needed.
• Flexibility: Useful for variable-length data storage.
• Improved Performance: More compact memory layout for specific operations.

Jagged arrays provide flexibility but should be used when necessary due to increased code complexity.