Java For Loop MCQ Questions and Answers

1. What is the basic structure of a for loop in Java?

a) for (initialization; condition; update) { // code }

b) for (condition; initialization; update) { // code }

c) for (condition) { // code }

d) for (initialization; update; condition) { // code }

Answer:

a) for (initialization; condition; update) { // code }

Explanation:

The standard for loop in Java consists of an initialization, a condition, and an update expression, all enclosed in parentheses.

2. Which part of a for loop is executed only once?

a) The condition

b) The initialization

c) The update statement

d) The code block

Answer:

b) The initialization

Explanation:

The initialization part of a for loop is executed only once at the beginning of the loop.

3. What is the For-Each loop primarily used for in Java?

a) To iterate over arrays or collections

b) To execute a block of code a specific number of times

c) To create infinite loops

d) To iterate in reverse order

Answer:

a) To iterate over arrays or collections

Explanation:

The For-Each loop in Java is used to iterate over elements in arrays or collections.

4. What is the syntax of a For-Each loop in Java?

a) for (type var : array) { // code }

b) for (type var = 0; var < array.length; var++) { // code }

c) foreach (type var in array) { // code }

d) for (var : type in array) { // code }

Answer:

a) for (type var : array) { // code }

Explanation:

The For-Each loop in Java uses the syntax 'for (type var : array)' where 'type' is the data type and 'var' is the variable that iterates over the array or collection.

5. What happens if the condition in a for loop is initially false?

a) The loop executes once

b) The loop's body does not execute

c) The loop becomes infinite

d) The loop skips to its last iteration

Answer:

b) The loop's body does not execute

Explanation:

If the condition in a for loop is initially false, the loop's body does not execute at all.

6. Which component of a for loop is optional?

a) Initialization

b) Condition

c) Update statement

d) All of the above

Answer:

d) All of the above

Explanation:

All components of a for loop (initialization, condition, and update statement) are optional. Omitting the condition can lead to an infinite loop.

7. Can the initialization block of a for loop declare multiple variables?

a) Yes, but only of the same type

b) Yes, of different types as well

c) No, it can only declare one variable

d) No, the initialization block is not for declaring variables

Answer:

a) Yes, but only of the same type

Explanation:

The initialization block of a for loop can declare multiple variables, but they must all be of the same type.

8. In a For-Each loop, is it possible to modify the current element?

a) Yes, the current element can be modified

b) No, the For-Each loop is read-only

c) Yes, but only in certain cases

d) No, unless using a special iterator

Answer:

b) No, the For-Each loop is read-only

Explanation:

The For-Each loop does not allow modification of the current element being iterated over. It is typically used for read-only operations.

9. What is the correct way to iterate over an array using a for loop?

a) for (int i = 0; i <= array.length; i++) { // code }

b) for (int i = 0; i < array.length; i++) { // code }

c) for (int i : array) { // code }

d) for (i = 0; i < array.length; i++) { // code }

Answer:

b) for (int i = 0; i < array.length; i++) { // code }

Explanation:

The correct way to iterate over an array using a for loop involves initializing 'i' to 0 and continuing while 'i' is less than the array's length.

10. How is the update statement in a for loop typically used?

a) To increment or decrement a loop counter

b) To check the loop's termination condition

c) To initialize loop variables

d) To perform a task at the end of each iteration

Answer:

a) To increment or decrement a loop counter

Explanation:

The update statement in a for loop is typically used to increment or decrement a loop counter, thereby progressing the loop towards its termination condition.

11. What will be the output of the following For-Each loop?

   int[] nums = {1, 2, 3};
   for (int num : nums) {
     System.out.print(num + " ");
   }

a) 1 2 3

b) 0 1 2

c) 1 2 3 4

d) An error occurs

Answer:

a) 1 2 3

Explanation:

The For-Each loop will iterate through each element of the array 'nums', printing each number followed by a space, resulting in the output "1 2 3".

12. Which statement is true about the initialization block in a for loop?

a) It can contain method calls.

b) It is executed before each iteration.

c) It must declare a new variable.

d) It can only initialize a single variable.

Answer:

a) It can contain method calls.

Explanation:

The initialization block of a for loop can contain method calls, variable declarations, or any other valid Java statement. It is executed only once, at the start of the loop.