Trailing closure syntax in Swift - Mini Project: Build & Apply

Trailing closure syntax

📖 Scenario: Imagine you are organizing a small event and want to print messages for each guest using a function that accepts a closure to customize the greeting.

🎯 Goal: You will create a function that takes a closure to print a greeting message. Then, you will call this function using trailing closure syntax to make your code cleaner and easier to read.

📋 What You'll Learn

Create a function called greetGuest that takes a closure parameter named message with no parameters and no return value.

Create a variable called guestName with the value "Alex".

Call the greetGuest function using trailing closure syntax to print a greeting message that includes the guestName.

Print the greeting message inside the closure.

💡 Why This Matters

🌍 Real World

Trailing closure syntax is often used in Swift when working with asynchronous tasks, animations, or event handlers to write cleaner and more readable code.

💼 Career

Understanding trailing closures helps you read and write Swift code more effectively, which is important for iOS app development and working with Swift frameworks.

1

Create the guest name variable

Create a variable called guestName and set it to the string "Alex".

Swift

# Create a variable called guestName and set it to "Alex"
# Your code here

Need a hint?

Use var guestName = "Alex" to create the variable.

2

Create the greetGuest function

Create a function called greetGuest that takes one parameter named message. This parameter is a closure with no parameters and no return value. The function should call the message closure inside its body.

Swift

var guestName = "Alex"
# Create the greetGuest function with a closure parameter named message
# Your code here

Need a hint?

Define the function with func greetGuest(message: () -> Void) and call message() inside.

3

Call greetGuest using trailing closure syntax

Call the greetGuest function using trailing closure syntax. Inside the closure, print the message "Hello, \(guestName)! Welcome to the event.".

Swift

var guestName = "Alex"

func greetGuest(message: () -> Void) {
    message()
}

# Call greetGuest using trailing closure syntax to print the greeting
# Your code here

Need a hint?

Use greetGuest { print("Hello, \(guestName)! Welcome to the event.") } to call the function.

4

Print the greeting message

Run the program to print the greeting message using the trailing closure syntax call to greetGuest.

Swift

var guestName = "Alex"

func greetGuest(message: () -> Void) {
    message()
}

greetGuest {
    print("Hello, \(guestName)! Welcome to the event.")
}

# Run the program to see the output
# Your code here

Need a hint?

Just run the program. The message should print automatically.