Why functions are first-class in Swift - See It in Action

Why functions are first-class in Swift

📖 Scenario: Imagine you are organizing a small event and want to assign different tasks to helpers. You want to keep track of these tasks and be able to pass them around easily to different people.

🎯 Goal: You will create simple functions representing tasks, store them in a list, and then call them one by one. This will show how functions in Swift can be treated like any other value.

📋 What You'll Learn

Create functions that print simple task messages

Store these functions in an array

Call each function from the array

Print the output of each function call

💡 Why This Matters

🌍 Real World

In real apps, you often pass functions as callbacks or handlers to respond to user actions or events.

💼 Career

Understanding first-class functions is key for Swift developers to write clean, modular, and reusable code.

1

Create simple task functions

Create two functions called taskOne and taskTwo. Each function should print a message: "Task One is done" and "Task Two is done" respectively.

Swift

// Create two functions taskOne and taskTwo that print messages
// Your code here

Need a hint?

Define each function with func keyword and use print inside the function body.

2

Store functions in an array

Create a variable called tasks and assign it an array containing the two functions taskOne and taskTwo.

Swift

func taskOne() {
    print("Task One is done")
}

func taskTwo() {
    print("Task Two is done")
}

// Create an array called tasks containing taskOne and taskTwo
// Your code here

Need a hint?

Use square brackets [] to create an array and list the function names without parentheses.

3

Call each function from the array

Use a for loop with variable task to iterate over tasks and call each function inside the loop.

Swift

func taskOne() {
    print("Task One is done")
}

func taskTwo() {
    print("Task Two is done")
}

let tasks = [taskOne, taskTwo]

// Use a for loop to call each function in tasks
// Your code here

Need a hint?

Inside the loop, call the function by adding parentheses () after the variable task.

4

Print the final output

Run the program to print the messages from both tasks. The output should show Task One is done and Task Two is done on separate lines.

Swift

func taskOne() {
    print("Task One is done")
}

func taskTwo() {
    print("Task Two is done")
}

let tasks = [taskOne, taskTwo]

for task in tasks {
    task()
}

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

Need a hint?

Just run the program. The print statements inside the functions will show the messages.