Implementing 2D Array Algorithms - AP Computer Science A

ArrayIndexOutOfBoundsException. Index 10 exceeds array bounds, throwing runtime exception.

To get the number of columns in the first row. Determines column count for the first row dimension.

Use nested loops with Math.random(). Generate random numbers and assign to each array position.

NullPointerException on access. Uninitialized array references are null, causing access errors.

int[][] array = {{1, 2, 3}, {4, 5, 6}};. Nested braces define rows and columns with literal values.

int[][] array = new int[3][4];. Creates array with specified row and column dimensions.

The entire second row. Returns reference to the one-dimensional array at index 1.

array[0].length. Access length property of any row to get column count.

1. Length property returns number of rows in the 2D array.

Use nested loops to iterate and print elements. Outer loop handles rows, inner loop handles columns for display.

Use nested loops to iterate and sum elements. Accumulate values using nested iteration through all elements.

ArrayIndexOutOfBoundsException. Negative indices are invalid and throw runtime exception.

int[][] array = {{1, 2}, {3, 4}};. Initializer lists create and populate array in one statement.

$O(1)$. Direct access by indices provides constant time complexity.

Rows can have different lengths. Unlike rectangular arrays, each row can have different column count.

Swap rows with columns. Transform rows into columns and columns into rows.

Arrays of arrays can be jagged; 2D arrays are rectangular. Array of arrays allows variable row sizes, 2D arrays are fixed.

Use System.arraycopy or a loop. Built-in method or manual iteration copies row elements.

Iterate and compare each element. Track maximum value while traversing all array elements.

ArrayIndexOutOfBoundsException. Index 5 exceeds valid column range, causing runtime error.

Use a loop: for (int i = 0; i < array[0].length; i++) array[0][i] = 0;. Loop through first row indices and assign zero values.

Number of rows (array.length). Returns the number of rows, not total elements.

array[1][2] = 5;. Assignment operator sets value at specific row-column position.

A grid of elements stored in rows and columns. Arrays organized in row-column structure for storing tabular data.

int[][] array;. Double brackets indicate two dimensions for row and column indices.

Rows can have different lengths. Unlike rectangular arrays, each row can have different column count.

int[][] array = {{1, 2}, {3, 4}};. Initializer lists create and populate array in one statement.

1. Last index is always length minus one in zero-based indexing.

Use two nested for loops. Outer loop for rows, inner loop for columns traverses all elements.