Capturing values from context in Swift - Mini Project: Build & Apply

Capturing Values from Context in Swift Closures

📖 Scenario: Imagine you are building a simple app that counts how many times a button is pressed. You want to use a closure to keep track of the count. This project will help you understand how closures capture values from their surrounding context in Swift.

🎯 Goal: You will create a closure that remembers the number of times it has been called by capturing a variable from its surrounding context. This will help you understand how closures can keep state in Swift.

📋 What You'll Learn

Create a variable called count initialized to 0

Create a closure called increment that increases count by 1 each time it is called

Call the increment closure 3 times

Print the final value of count

💡 Why This Matters

🌍 Real World

Closures that capture values are used in apps to keep track of state, like counting button taps or managing animations.

💼 Career

Understanding how closures capture values is important for iOS developers to write clean, efficient, and bug-free code.

1

Create the count variable

Create a variable called count and set it to 0.

Swift

// Create a variable called count and set it to 0
// Your code here

Need a hint?

Use var count = 0 to create a variable that can change.

2

Create the increment closure

Create a closure called increment that adds 1 to the variable count each time it is called.

Swift

var count = 0

// Create a closure called increment that adds 1 to count
// Your code here

Need a hint?

Define increment as a closure with let increment = { ... } and inside add count += 1.

3

Call the increment closure 3 times

Call the closure increment exactly three times to increase count.

Swift

var count = 0

let increment = {
    count += 1
}

// Call increment three times
// Your code here

Need a hint?

Call increment() three times, each on its own line.

4

Print the final value of count

Write a print statement to display the final value of count.

Swift

var count = 0

let increment = {
    count += 1
}

increment()
increment()
increment()

// Print the value of count
// Your code here

Need a hint?

Use print(count) to show the number 3.