Type inference by the compiler in Swift - Mini Project: Build & Apply

Type inference by the compiler

📖 Scenario: Imagine you are creating a simple Swift program to store information about a fruit basket. You want to use the compiler's ability to guess the type of your variables automatically, so you don't have to write the type explicitly.

🎯 Goal: Build a Swift program that uses type inference to create variables for fruit names and quantities, then prints them.

📋 What You'll Learn

Create variables using type inference with exact names and values

Add a constant to hold the total number of fruits

Use a for loop to print each fruit and its quantity

Print the total number of fruits at the end

💡 Why This Matters

🌍 Real World

Type inference helps programmers write cleaner and shorter code by letting the compiler figure out data types automatically.

💼 Career

Understanding type inference is important for Swift developers to write efficient and readable code, especially in app development.

1

Create variables with type inference

Create three variables called appleCount, bananaCount, and orangeCount with values 5, 3, and 7 respectively. Do not specify their types explicitly.

Swift

# Create variables appleCount, bananaCount, and orangeCount with values 5, 3, and 7
# Your code here

Need a hint?

Just write var appleCount = 5 and similarly for the others. Swift will guess the type as Int.

2

Add a constant for total fruits

Create a constant called totalFruits that adds appleCount, bananaCount, and orangeCount. Use type inference and do not specify the type explicitly.

Swift

var appleCount = 5
var bananaCount = 3
var orangeCount = 7
# Create a constant totalFruits that sums appleCount, bananaCount, and orangeCount
# Your code here

Need a hint?

Use let totalFruits = appleCount + bananaCount + orangeCount to create the constant.

3

Use a for loop to print each fruit and quantity

Create a dictionary called fruitBasket with keys "Apple", "Banana", and "Orange" and their respective counts from appleCount, bananaCount, and orangeCount. Then use a for loop with variables fruit and count to iterate over fruitBasket and print each fruit and its count using print("\(fruit): \(count)").

Swift

var appleCount = 5
var bananaCount = 3
var orangeCount = 7
let totalFruits = appleCount + bananaCount + orangeCount
# Create fruitBasket dictionary and use for loop to print fruit and count
# Your code here

Need a hint?

Use a dictionary literal and a for loop with tuple unpacking to print each fruit and count.

4

Print the total number of fruits

Write a print statement to display the text Total fruits: followed by the value of totalFruits using string interpolation.

Swift

var appleCount = 5
var bananaCount = 3
var orangeCount = 7
let totalFruits = appleCount + bananaCount + orangeCount

let fruitBasket = ["Apple": appleCount, "Banana": bananaCount, "Orange": orangeCount]

for (fruit, count) in fruitBasket {
    print("\(fruit): \(count)")
}
# Print the total number of fruits
# Your code here

Need a hint?

Use print("Total fruits: \(totalFruits)") to show the total count.