Arrays

Question 1

What are the 3 ways to instantiate an array?

Answer 1

int[] arr1 = new int[3];
int[] arr2 = { 1, 2, 3 };
int[] arr3 = new int[] { 1, 2, 3 };

Question 2

What are the 2 ways to instantiate multidimensional arrays?

Answer 2

int[][] matrix = new [1][2];
int[][] matrix2 = {{1,2}};

Question 3

What class could you use to create a stream out of an array?

Answer 3

int[][] matrix = {{1,2,3}};
Arrays.stream(matrix)...

Question 4

1. What data structure is used to implement varargs?
2. Code an example using varargs

Answer 4

1. arrays

2.  void sum(int... args) {
       Arrays.stream(args).sum();
   }

Question 5

How can an array be converted to a List?

Answer 5

Integer[] arr = { 1, 2, 3 };
List<Integer> list = Arrays.asList(arr);
 List<Integer> list2 = List.of(arr);
System.out.println(list); // [1, 2, 3]
System.out.println(list2); // [1, 2, 3]

Question 6

What will the code bellow print?

int[] nums = {1,2,3};
int[] nums2 = {1,2,3};

System.out.println(nums == nums2);
System.out.println(Arrays.equals(nums, nums2));

Answer 6

1. False
2. True