Why loop control is required in Java - Challenge Your Understanding

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Java loop with break?

Consider the following Java code snippet. What will it print?

Java

public class Test {
    public static void main(String[] args) {
        for (int i = 0; i < 5; i++) {
            if (i == 3) {
                break;
            }
            System.out.print(i + " ");
        }
    }
}

A 0 1 2 3

B 0 1 2 3 4

C 0 1 2

D 3 4

💡 Hint

The break statement stops the loop when i equals 3.

The loop prints numbers starting from 0. When i reaches 3, the break stops the loop immediately, so 3 and 4 are not printed.

❓ Predict Output

intermediate

What does this Java loop with continue print?

Look at this Java code. What will be printed?

Java

public class Test {
    public static void main(String[] args) {
        for (int i = 0; i < 5; i++) {
            if (i == 2) {
                continue;
            }
            System.out.print(i + " ");
        }
    }
}

A 0 1 2 3 4

B 0 1 3 4

C 2 3 4

D 0 1 2 4

💡 Hint

The continue statement skips the current loop iteration when i is 2.

When i is 2, continue skips the print statement for that iteration, so 2 is not printed.

🧠 Conceptual

advanced

Why is loop control important in programming?

Which of the following best explains why loop control statements like break and continue are required?

A They help to stop or skip parts of the loop to avoid infinite loops or unwanted processing.

B They allow changing the loop variable automatically without manual update.

C They make the loop run faster by optimizing CPU usage automatically.

D They replace the need for conditional statements inside loops.

💡 Hint

Think about what happens if a loop never stops or processes unnecessary steps.

Loop control statements let us stop loops early or skip certain steps, which helps prevent infinite loops and improves efficiency.

❓ Predict Output

advanced

What is the output of nested loops with break?

What will this Java program print?

Java

public class Test {
    public static void main(String[] args) {
        for (int i = 1; i <= 3; i++) {
            for (int j = 1; j <= 3; j++) {
                if (j == 2) {
                    break;
                }
                System.out.print(i + "-" + j + " ");
            }
        }
    }
}

A 1-1 2-1 3-1

B 1-1 1-2 2-1 2-2 3-1 3-2

C 1-1 2-1 3-1 3-2

D 1-1 2-1 2-2 3-1

💡 Hint

The inner loop breaks when j equals 2, so only j=1 prints each time.

For each i, the inner loop prints only when j=1. When j=2, break stops the inner loop, so output is '1-1 2-1 3-1 '.

❓ Predict Output

expert

What error does this Java loop cause?

What error will this Java code produce when run?

Java

public class Test {
    public static void main(String[] args) {
        int i = 0;
        while (i < 5) {
            System.out.print(i + " ");
        }
    }
}

A Runtime error: NullPointerException

B No error, prints 0 1 2 3 4

C Compilation error: missing increment of i

D Infinite loop printing 0 forever

💡 Hint

Check if the loop variable changes inside the loop.

Variable i never changes, so condition i < 5 is always true, causing an infinite loop printing 0 repeatedly.