Break and continue behavior in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the break statement do inside a loop in Swift?

The break statement immediately stops the entire loop and exits it, continuing execution after the loop.

beginner

What is the purpose of the continue statement in Swift loops?

The continue statement skips the rest of the current loop iteration and moves to the next iteration of the loop.

intermediate

In Swift, what happens if you use break inside a nested loop?

The break statement only exits the innermost loop where it is called, not all outer loops.

intermediate

Can continue be used in a switch statement in Swift?

No, <code>continue</code> is used in loops, not in <code>switch</code> statements. To skip cases in <code>switch</code>, you use <code>fallthrough</code> or just let the case end.

beginner

How does break differ from continue in Swift loops?

break stops the whole loop immediately, while continue skips only the current iteration and continues with the next one.

What will happen if a break statement is executed inside a Swift for loop?

A The loop restarts from the beginning.

B The current iteration is skipped, and the loop continues.

C The loop stops immediately and exits.

D Nothing, the loop continues normally.

The break statement immediately stops the loop and exits it.

What does the continue statement do in a Swift loop?

A Stops the entire loop.

B Skips the rest of the current iteration and moves to the next iteration.

C Exits the function.

D Restarts the loop from the first iteration.

continue skips the rest of the current iteration and proceeds with the next one.

If break is used inside a nested loop, which loop does it exit?

A Only the innermost loop where <code>break</code> is called.

B All loops at once.

C The outermost loop.

D It causes an error.

break exits only the innermost loop it is inside.

Can continue be used to skip a case in a Swift switch statement?

A Yes, it skips the case.

B No, you must use <code>break</code> instead.

C Yes, but only in <code>switch</code> with loops.

D No, <code>continue</code> is only for loops.

continue is used only in loops, not in switch statements.

Which statement best describes the difference between break and continue in Swift loops?

A <code>break</code> stops the loop; <code>continue</code> skips current iteration.

B <code>break</code> skips current iteration; <code>continue</code> stops the loop.

C Both stop the loop immediately.

D Both skip the current iteration.

break stops the loop; continue skips the current iteration and continues.

Explain how break and continue behave inside Swift loops and how they differ.

Think about what happens to the loop after each statement runs.

Describe what happens when break is used inside nested loops in Swift.

Consider which loop the break affects.

Practice

1. What does the break statement do inside a Swift loop?

easy

A. Restarts the loop from the beginning.

B. Skips the current iteration and continues with the next one.

C. Pauses the loop until a condition is met.

D. Stops the entire loop immediately and exits it.

Solution

1. Step 1: Understand the role of break in loops

   The break statement immediately stops the loop and exits it, no matter where it is in the loop.

2. Step 2: Compare with other options

   continue skips to the next iteration, but break stops the loop entirely. Restarting or pausing the loop is not the behavior of break.

3. Final Answer:

   Stops the entire loop immediately and exits it. -> Option D

4. Quick Check:

   break stops loop [OK]

Hint: Break means stop the loop completely [OK]

Common Mistakes:

• Confusing break with continue
• Thinking break restarts the loop
• Assuming break pauses the loop

2. Which of the following is the correct syntax to skip the current iteration in a Swift for loop?

easy

A. skip

B. continue

C. break

D. stop

Solution

1. Step 1: Identify the keyword to skip iteration

   In Swift, continue is used to skip the rest of the current loop iteration and move to the next one.

2. Step 2: Verify other options

   break stops the loop, skip and stop are not valid Swift keywords for loops.

3. Final Answer:

   continue -> Option B

4. Quick Check:

   Skip iteration = continue [OK]

Hint: Use continue to skip current loop step [OK]

Common Mistakes:

• Using break instead of continue
• Using non-existent keywords like skip or stop
• Confusing continue with break

3. What will be the output of this Swift code?

for i in 1...5 {
    if i == 3 {
        break
    }
    print(i)
}

medium

A. 1 2

B. No output

C. 3 4 5

D. 1 2 3 4 5

Solution

1. Step 1: Analyze the loop and break condition

   The loop runs from 1 to 5. When i equals 3, break stops the loop immediately.

2. Step 2: Determine printed values before break

   Values 1 and 2 are printed before reaching 3. At 3, loop stops, so 3, 4, 5 are not printed.

3. Final Answer:

   1 2 -> Option A

4. Quick Check:

   Break stops at 3, prints before it [OK]

Hint: Break stops loop before printing 3 [OK]

Common Mistakes:

• Assuming break skips only current iteration
• Thinking all numbers print
• Confusing break with continue

4. Find the error in this Swift code snippet:

for i in 1...5 {
    if i == 3 {
        continue
    }
    if i == 6 {
        break
    }
    print(i)
}

medium

A. break should come before continue in the code.

B. continue cannot be used inside a for loop.

C. The loop will never break because i never reaches 6.

D. The range 1...5 is invalid.

Solution

1. Step 1: Check the loop range and conditions

   The loop runs from 1 to 5, so i will never be 6.

2. Step 2: Analyze the break condition

   Since i == 6 never occurs, the break statement will never execute, so the loop runs fully except skipping 3 due to continue.

3. Final Answer:

   The loop will never break because i never reaches 6. -> Option C

4. Quick Check:

   Break condition unreachable [OK]

Hint: Check if break condition can ever be true [OK]

Common Mistakes:

• Thinking continue is invalid in for loops
• Assuming break runs before continue always
• Not checking loop range carefully

5. You want to print all numbers from 1 to 10 except 5 and stop printing after 8. Which code snippet correctly uses break and continue in Swift?

hard

A. for i in 1...10 {
if i == 5 { continue }
if i > 8 { break }
print(i)
}

B. for i in 1...10 {
if i == 5 { break }
if i > 8 { continue }
print(i)
}

C. for i in 1...10 {
if i == 5 { continue }
if i > 7 { continue }
print(i)
}

D. for i in 1...10 {
if i == 5 { break }
if i > 8 { break }
print(i)
}

Solution

1. Step 1: Understand requirements

   Skip printing 5 (use continue) and stop printing after 8 (use break when > 8).

2. Step 2: Check each option

   for i in 1...10 { if i == 5 { continue } if i > 8 { break } print(i) } uses continue to skip 5 and break to stop after 8, matching requirements exactly.

3. Final Answer:

   for i in 1...10 { if i == 5 { continue } if i > 8 { break } print(i) } -> Option A

4. Quick Check:

   Continue skips 5, break stops loop after 8 [OK]

Hint: Continue skips, break stops loop [OK]

Common Mistakes:

• Using break to skip 5 instead of continue
• Using continue to stop loop after 8
• Mixing order of break and continue incorrectly