Why while loop is needed in Java - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print numbers from 1 to 5 using a while loop.

Java

int i = 1;
while (i [1] 5) {
    System.out.println(i);
    i++;
}

Drag options to blanks, or click blank then click option'

A<=

B<

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using > or >= will cause the loop to never run or run incorrectly.

The condition i <= 5 makes the loop run while i is less than or equal to 5, printing 1 to 5.

2fill in blank

medium

Complete the code to keep asking the user for input until they enter 0.

Java

Scanner scanner = new Scanner(System.in);
int num;
do {
    System.out.print("Enter a number: ");
    num = scanner.nextInt();
} while (num [1] 0);

Drag options to blanks, or click blank then click option'

A==

B<

C!=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using == will stop the loop immediately if the first input is not zero.

The loop continues while the number is not equal to 0, so it stops when the user enters 0.

3fill in blank

hard

Fix the error in the while loop condition to avoid an infinite loop.

Java

int count = 0;
while (count [1] 5) {
    System.out.println(count);
    count++;
}

Drag options to blanks, or click blank then click option'

A<

B<=

C>

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using >= or > will cause the loop to never run.

The condition count < 5 makes the loop run 5 times, printing 0 to 4.

4fill in blank

hard

Fill both blanks to create a while loop that prints even numbers less than 10.

Java

int num = 0;
while (num [1] 10) {
    if (num % 2 == 0) {
        System.out.println(num);
    }
    num[2];
}

Drag options to blanks, or click blank then click option'

A<

B++

C--

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using -- will decrease num and cause an infinite loop.

The loop runs while num is less than 10, and num is increased by 1 each time to avoid infinite loop.

5fill in blank

hard

Fill all three blanks to create a while loop that sums numbers from 1 to 5.

Java

int sum = 0;
int i = 1;
while (i [1] 5) {
    sum [2] i;
    i[3];
}
System.out.println(sum);

Drag options to blanks, or click blank then click option'

A<=

B+=

C++

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of <= will miss adding 5 to sum.

Forgetting to increment i causes infinite loop.

The loop runs while i is less than or equal to 5, adds i to sum, and increments i by 1 each time.