Java Arrays Worksheet

A programmer wants to store the ages of 50 students using a single variable name. What should they use?

• Class

• Array

• Loop

• Method

Which of the following best defines an array in Java?

• A list of random variables

• A collection of variables of different types

• A fixed-size sequential collection of elements of the same type

• A method to sort data automatically

In Java, what is the index of the first element in an array?

• -1

• 0

• 1

• Depends on declaration

What is the key advantage of arrays?

• They can grow automatically

• They provide random access to elements

• They are faster than loops

• They can hold different data types

A developer wants to store the names of 7 days. What array declaration is correct?

• String days = {"Mon","Tue","Wed"};

• string[] days = {"Mon","Tue","Wed","Thu","Fri","Sat","Sun"};

• days = new String("Mon");

• string days[7] = new String();

Which correctly declares and allocates an array of 10 integers?

• int a = new int(10);

• int[] a = new int[10];

• int a[10];

• new int a[10];

What is the output of the code below? int[] nums = {1,2,3,4,5}; System.out.println(nums[2]);

• 1

• 2

• 3

A student writes int arr[] = new int[5]; How many elements can be stored?

• 4

• 5

• 6

• Unlimited

Which syntax both declares and initializes an array?

• int[] nums = new int[5];

• int nums[] = {10, 20, 30, 40, 50};

• int[] nums; nums = {10,20,30};

• int nums = [10,20,30];

A student initializes String[] names = new String[3]; but doesn’t assign values. What is stored by default?

• null

• ""

• 0

• undefined