Explicit type annotation in Swift - Mini Project: Build & Apply

Explicit type annotation

📖 Scenario: You are organizing a small library system where you keep track of the number of books available in different genres.

🎯 Goal: You will create variables with explicit type annotations to store the number of books in each genre, then calculate the total number of books.

📋 What You'll Learn

Create variables with explicit type annotations for book counts

Use integer type Int for the counts

Calculate the total number of books using these variables

Print the total number of books

💡 Why This Matters

🌍 Real World

Explicit type annotations help programmers clearly define what kind of data each variable holds, which reduces mistakes and makes code easier to read and maintain.

💼 Career

Many software development jobs require writing clear and type-safe code. Understanding explicit type annotations is essential for working with Swift and other typed languages.

1

Create book count variables with explicit type annotation

Create three variables with explicit type annotation Int named fictionCount, historyCount, and scienceCount. Set their values to 12, 8, and 15 respectively.

Swift

// Create variables fictionCount, historyCount, and scienceCount with type Int and assign values
// Your code here

Need a hint?

Use var variableName: Int = value to declare variables with explicit type annotation.

2

Create a variable to hold the total count

Create a variable called totalBooks with explicit type annotation Int and set it to 0.

Swift

var fictionCount: Int = 12
var historyCount: Int = 8
var scienceCount: Int = 15

// Create variable totalBooks with type Int and initial value 0
// Your code here

Need a hint?

Remember to specify the type Int explicitly when declaring totalBooks.

3

Calculate the total number of books

Add the values of fictionCount, historyCount, and scienceCount and assign the result to totalBooks.

Swift

var fictionCount: Int = 12
var historyCount: Int = 8
var scienceCount: Int = 15
var totalBooks: Int = 0

// Calculate totalBooks by adding fictionCount, historyCount, and scienceCount
// Your code here

Need a hint?

Use the + operator to add the counts and assign to totalBooks.

4

Print the total number of books

Write a print statement to display the value of totalBooks.

Swift

var fictionCount: Int = 12
var historyCount: Int = 8
var scienceCount: Int = 15
var totalBooks: Int = 0
totalBooks = fictionCount + historyCount + scienceCount

// Print the totalBooks value
// Your code here

Need a hint?

Use print(totalBooks) to show the total number of books.