Labeled statements for nested loops in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested loops with labeled break

What is the output of this Swift code using labeled break in nested loops?

Swift

outerLoop: for i in 1...3 {
    for j in 1...3 {
        if i * j == 4 {
            break outerLoop
        }
        print("\(i),\(j)")
    }
}

A

1,1
1,2
1,3
2,1
2,2

B

1,1
1,2
2,1
2,2
3,1

C

1,1
1,2
1,3
2,1
2,2
3,1
3,2
3,3

D

1,1
1,2
1,3
2,1

💡 Hint

Remember that break with a label exits the entire labeled loop, not just the inner loop.

The code prints pairs (i,j) until i*j equals 4. When i=2 and j=2, i*j=4, so break outerLoop executes before the print, stopping all loops without printing 2,2. Prints: 1,1 1,2 1,3 2,1.

❓ Predict Output

intermediate

Output of nested loops with labeled continue

What is the output of this Swift code using labeled continue in nested loops?

Swift

outer: for i in 1...2 {
    for j in 1...3 {
        if j == 2 {
            continue outer
        }
        print("\(i),\(j)")
    }
}

A

1,1
2,1

B

1,1
1,3
2,1
2,3

C

1,1
2,1
2,3

D

1,1
1,3
2,1
2,3
1,2
2,2

💡 Hint

Labeled continue skips the rest of the current iteration of the labeled loop.

When j == 2, continue outer skips the print for j=2 and remaining j=3, advancing to next i. Prints only j=1 for i=1 and i=2: 1,1 and 2,1.

🧠 Conceptual

advanced

Purpose of labeled statements in nested loops

Why are labeled statements useful in nested loops in Swift?

A They allow breaking or continuing an outer loop directly from an inner loop.

B They improve the performance of nested loops by optimizing memory.

C They automatically parallelize nested loops for faster execution.

D They replace the need for functions inside loops.

💡 Hint

Think about controlling which loop to break or continue when loops are inside each other.

Labeled statements let you specify which loop to break or continue, useful when you want to exit or skip iterations of an outer loop from inside an inner loop.

🔧 Debug

advanced

Identify the error in labeled break usage

What error occurs when running this Swift code?

Swift

for i in 1...3 {
    innerLoop: for j in 1...3 {
        if i == j {
            break outerLoop
        }
        print(i, j)
    }
}

A Runtime error: index out of range

B Compile-time error: 'outerLoop' label not found

C No error, prints pairs until i == j

D Compile-time error: missing colon after label

💡 Hint

Check if the label used in break exists in the code.

The code tries to break 'outerLoop' but no such label is defined. The only label is 'innerLoop', so compiler reports label not found error.

❓ Predict Output

expert

Count iterations with labeled continue in nested loops

What is the value of 'count' after running this Swift code?

Swift

var count = 0
outer: for i in 1...3 {
    for j in 1...3 {
        if i + j == 4 {
            continue outer
        }
        count += 1
    }
}

A 5

B 7

C 3

D 9

💡 Hint

Each time i+j equals 4, the code skips to the next i, skipping remaining j values.

When i+j==4, continue outer skips count +=1 for that j and all subsequent j for that i. - i=1: j=1 (+1), j=2 (+1), j=3 (skip +1, next i) - i=2: j=1 (+1), j=2 (skip, next i) - i=3: j=1 (skip, end) Total: 3.