Labeled statements for nested loops in Swift - Mini Project: Build & Apply

Labeled statements for nested loops

📖 Scenario: Imagine you are checking a grid of seats in a theater to find the first empty seat. The seats are arranged in rows and columns.

🎯 Goal: You will write a Swift program that uses labeled statements to break out of nested loops when the first empty seat is found.

📋 What You'll Learn

Create a 2D array called seats representing rows and columns with exact values

Create a label called searchSeats for the outer loop

Use nested for loops to iterate over rows and columns

Use break searchSeats to exit both loops when an empty seat is found

Print the row and column of the first empty seat found

💡 Why This Matters

🌍 Real World

Finding the first available seat in a theater or airplane seating chart is a common real-world task that requires checking nested data structures.

💼 Career

Understanding labeled statements and nested loops helps in writing efficient code for searching and processing multi-dimensional data, useful in software development and data analysis.

1

Create the seats grid

Create a 2D array called seats with these exact values: [["X", "X", "O"], ["X", "O", "X"], ["X", "X", "X"]]. Each "X" means occupied and "O" means empty.

Swift

# Create the seats array with the exact values
# Your code here

Need a hint?

Use let seats = [["X", "X", "O"], ["X", "O", "X"], ["X", "X", "X"]] to create the grid.

2

Add the label for the outer loop

Add a label called searchSeats before the outer for loop that iterates over the rows of seats.

Swift

let seats = [["X", "X", "O"], ["X", "O", "X"], ["X", "X", "X"]]

// Add the label searchSeats before the outer loop
# Your code here

Need a hint?

Write searchSeats: for row in 0.. to label the outer loop.

3

Add nested loop and break with label

Inside the labeled outer loop searchSeats, add an inner for loop with variable col iterating over 0 to seats[row].count. Use if seats[row][col] == "O" to check for an empty seat and then use break searchSeats to exit both loops.

Swift

let seats = [["X", "X", "O"], ["X", "O", "X"], ["X", "X", "X"]]

searchSeats: for row in 0..<seats.count {
    // Add inner loop and break with label here
    # Your code here
}

Need a hint?

Use for col in 0.. and inside it check if seats[row][col] == "O" then break searchSeats.

4

Print the first empty seat position

Add two variables foundRow and foundCol initialized to -1 before the loops. Inside the if seats[row][col] == "O" block, set foundRow = row and foundCol = col before break searchSeats. After the loops, print "First empty seat found at row \(foundRow), column \(foundCol)".

Swift

let seats = [["X", "X", "O"], ["X", "O", "X"], ["X", "X", "X"]]

// Add foundRow and foundCol variables
var foundRow = -1
var foundCol = -1

searchSeats: for row in 0..<seats.count {
    for col in 0..<seats[row].count {
        if seats[row][col] == "O" {
            // Set foundRow and foundCol here
            # Your code here
            break searchSeats
        }
    }
}

// Print the result
# Your code here

Need a hint?

Remember to set foundRow = row and foundCol = col before breaking. Then print the message with those variables.