Test: Arrays - 2 - EmSAT Achieve MCQ

The correct syntax for declaring and initializing an array in Java is to use "int[] arr = new int[5];".

The length of an array in Java is equal to the number of elements it contains. It can be accessed using the "length" property of the array.

An ArrayIndexOutOfBoundsException occurs when attempting to access an index outside the valid range of the array (i.e., negative index or index greater than or equal to the array length).

The enhanced for loop in Java automatically handles the initialization, condition, and increment parts. It simplifies the iteration over arrays and collections.

The Arrays.copyOfRange() method in Java copies a subset of elements from one array to another, starting at a specific index and ending at another index.

The code initializes an integer array "numbers" with elements {1, 2, 3, 4, 5}. The statement "System.out.println(numbers[2]);" prints the value at index 2, which is 3.

The code initializes an integer array "numbers" with elements {1, 2, 3, 4, 5}. The statement "System.out.println(numbers.length);" prints the length of the array, which is 5.

The code tries to access index 10 of the array "numbers", which is beyond the valid range (0 to 4). This will throw an ArrayIndexOutOfBoundsException.

The code initializes an integer array "numbers" with elements {1, 2, 3, 4, 5}. The enhanced for loop iterates over each element of the array and prints it.

The code initializes an integer array "numbers" with elements {1, 2, 3, 4, 5}. The Arrays.copyOfRange() method is used to copy a subset of elements from index 1 to 4 (exclusive) and store it in the "copied" array. The "Arrays.toString()" method is used to print the contents of the "copied" array.

The code initializes a 2D integer array "matrix" with elements {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}. The variable "max" is initially set to the value at index (0, 0) of the matrix. The nested for loop iterates over each element of the matrix and updates the "max" value if a greater number is found. Finally, the maximum value is printed, which is 9.

The code initializes a jagged integer array "jagged" with elements {{1, 2}, {3, 4, 5}, {6, 7, 8, 9}}. The variable "oddCount" is initially set to 0. The nested for loop iterates over each element of the jagged array and increments "oddCount" if an odd number is found. Finally, the count of odd numbers is printed, which is 5.

The code initializes a 3D integer array "cube" with elements {{{1, 2}, {3, 4}}, {{5, 6}, {7, 8}}}. The variable "sum" is initially set to 0. The nested for loop iterates over each element of the cube array and adds it to the "sum" variable. Finally, the sum of all elements is printed, which is 18.

The code initializes a 2D integer array "matrix" with elements {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}. The variables "sum" and "count" are initially set to 0. The nested for loop iterates over each element of the matrix array, adds the element to the "sum" variable, and increments the "count" variable. Finally, the average of all elements is computed and printed, which is 4.5.

The code initializes a 2D integer array "matrix" with elements {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}. The code creates a new 2D integer array "transpose" with dimensions swapped from the "matrix" array. The nested for loop iterates over each element of the "matrix" array and assigns it to the corresponding position in the "transpose" array. Finally, the "transpose" array is printed, which represents the transpose of the "matrix" array.