Labeled break and continue in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to break out of the outer loop using a label.

Javascript

outerLoop: for (let i = 0; i < 3; i++) {
  for (let j = 0; j < 3; j++) {
    if (i === 1 && j === 1) {
      [1] outerLoop;
    }
  }
}

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

Areturn

Bcontinue

Cexit

Dbreak

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'continue' instead of 'break' to exit the loop.

Forgetting to add the label after 'break'.

The 'break' statement with a label exits the labeled loop immediately.

2fill in blank

medium

Complete the code to continue the outer loop when a condition is met.

Javascript

outer: for (let i = 0; i < 3; i++) {
  for (let j = 0; j < 3; j++) {
    if (j === 1) {
      [1] outer;
    }
  }
}

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

Acontinue

Bbreak

Creturn

Dstop

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'break' instead of 'continue' to skip iterations.

Not specifying the label after 'continue'.

The 'continue' statement with a label skips to the next iteration of the labeled loop.

3fill in blank

hard

Fix the error in the labeled continue statement.

Javascript

outerLoop: for (let i = 0; i < 2; i++) {
  for (let j = 0; j < 2; j++) {
    if (i === j) {
      [1] outerLoop;
    }
  }
}

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

Acontinue

Bcontinuee

Cbreakk

Dbreak

Attempts:

3 left

💡 Hint

Common Mistakes

Misspelling 'continue' as 'continuee'.

Using 'break' when 'continue' is needed.

The correct keyword is 'continue' to skip to the next iteration of the labeled loop.

4fill in blank

hard

Fill both blanks to correctly use labeled break and continue in nested loops.

Javascript

outer: for (let i = 0; i < 3; i++) {
  inner: for (let j = 0; j < 3; j++) {
    if (i === 1 && j === 1) {
      [1] outer;
    }
    if (j === 2) {
      [2] inner;
    }
  }
}

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

Abreak

Bcontinue

Creturn

Dexit

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up 'break' and 'continue' keywords.

Using wrong labels or missing labels.

Use 'break outer;' to exit the outer loop and 'continue inner;' to skip to the next iteration of the inner loop.

5fill in blank

hard

Fill all three blanks to create a labeled loop that breaks and continues correctly.

Javascript

outerLoop: for (let i = 0; i < 4; i++) {
  innerLoop: for (let j = 0; j < 4; j++) {
    if (i === 2 && j === 2) {
      [1] outerLoop;
    }
    if (j === 3) {
      [2] innerLoop;
    }
    console.log(i, j);
  }
  if (i === 3) {
    [3];
  }
}

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

Abreak

Bcontinue

Creturn

Dbreak outerLoop

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'break' without label to exit outer loop.

Using 'continue' without label to skip inner loop.

Confusing 'return' with 'break' or 'continue'.

Use 'break outerLoop;' to exit the outer loop, 'continue innerLoop;' to skip inner loop iterations, and 'return;' to exit the function.

Practice

1.

What does the break label; statement do in JavaScript?

easy

A. It exits the loop identified by the label immediately.

B. It skips the current iteration of the inner loop only.

C. It restarts the entire program from the beginning.

D. It pauses the loop until a condition is met.

Solution

1. Step 1: Understand labeled break

   The break label; statement exits the loop that has the specified label, not just the innermost loop.

2. Step 2: Compare with normal break

   Normal break exits only the current loop, but labeled break exits the labeled outer loop immediately.

3. Final Answer:

   It exits the loop identified by the label immediately. -> Option A

4. Quick Check:

   break label exits labeled loop [OK]

Hint: Labeled break exits the named loop, not just inner loop [OK]

Common Mistakes:

• Thinking break label only skips current iteration
• Confusing break label with continue label
• Assuming break label pauses the loop

2.

Which of the following is the correct syntax to continue the outer loop labeled outerLoop?

outerLoop: for(let i = 0; i < 3; i++) {
  for(let j = 0; j < 3; j++) {
    // What goes here?
  }
}

easy

A. continue outerLoop;

B. continue (outerLoop);

C. continue: outerLoop;

D. continue to outerLoop;

Solution

1. Step 1: Recall labeled continue syntax

   The correct syntax to continue a labeled loop is continue labelName; without parentheses or extra words.

2. Step 2: Match options with syntax

   continue outerLoop; matches the correct syntax exactly. Options B, C, and D are invalid syntax.

3. Final Answer:

   continue outerLoop; -> Option A

4. Quick Check:

   continue labelName; is correct syntax [OK]

Hint: Use 'continue label;' exactly, no parentheses or colons [OK]

Common Mistakes:

• Adding parentheses around label
• Using colon after continue
• Writing extra words like 'to'

3.

What is the output of the following code?

outer: for(let i = 1; i <= 3; i++) {
  for(let j = 1; j <= 3; j++) {
    if(j === 2) continue outer;
    console.log(i, j);
  }
}

medium

A. 1 1
1 3
2 1
3 1

B. 1 1
2 1
3 1

C. 1 1
1 3
2 1
2 3
3 1
3 3

D. 1 1
2 2
3 3

Solution

1. Step 1: Understand continue outer;

   When j === 2, continue outer; skips to the next iteration of the outer loop, skipping the rest of inner loop and console.log for that i.

2. Step 2: Trace iterations

   For i=1: j=1 logs '1 1', j=2 triggers continue outer (skip to i=2). For i=2: j=1 logs '2 1', j=2 triggers continue outer (skip to i=3). For i=3: j=1 logs '3 1', j=2 triggers continue outer (loop ends after i=3).

3. Final Answer:

   1 1 2 1 3 1 -> Option B

4. Quick Check:

   continue outer skips inner loop rest [OK]

Hint: continue label skips to next outer loop iteration [OK]

Common Mistakes:

• Thinking continue outer skips only inner iteration
• Expecting all inner loop logs
• Confusing break and continue effects

4.

Find the error in this code snippet:

outerLoop: for(let i = 0; i < 2; i++) {
  for(let j = 0; j < 2; j++) {
    if(i === j) break;
    if(j === 1) continue outerLoop;
    console.log(i, j);
  }
}

medium

A. The label name is missing a colon.

B. Using continue outerLoop; inside inner loop is invalid.

C. The break; statement breaks only inner loop, not labeled loop.

D. No error; code runs correctly.

Solution

1. Step 1: Analyze break statement

   The break; without label breaks only the innermost loop, not the labeled outer loop.

2. Step 2: Check labeled continue usage

   The continue outerLoop; is valid and skips to next iteration of the labeled loop.

3. Final Answer:

   The break; statement breaks only inner loop, not labeled loop. -> Option C

4. Quick Check:

   break without label affects inner loop only [OK]

Hint: break without label breaks inner loop only [OK]

Common Mistakes:

• Assuming break breaks labeled loop without label
• Thinking continue outerLoop is invalid
• Confusing label syntax

5.

Given the nested loops below, how can you skip all remaining iterations of the outer loop when j === 3?

outerLoop: for(let i = 1; i <= 5; i++) {
  for(let j = 1; j <= 5; j++) {
    if(j === 3) {
      // What statement here?
    }
    console.log(i, j);
  }
}

hard

A. continue outerLoop;

B. break;

C. continue;

D. break outerLoop;

Solution

1. Step 1: Understand the goal

   We want to stop all remaining iterations of the outer loop when j === 3, meaning exit the outer loop completely.

2. Step 2: Choose correct statement

   break outerLoop; exits the labeled outer loop immediately. Plain break; exits only inner loop. continue; and continue outerLoop; skip iterations but do not exit the outer loop.

3. Final Answer:

   break outerLoop; -> Option D

4. Quick Check:

   break label exits labeled loop [OK]

Hint: Use break label to exit outer loop immediately [OK]

Common Mistakes:

• Using break without label to exit outer loop
• Using continue instead of break
• Confusing continue label with break label