Type conversion is always explicit in Swift - Mini Project: Build & Apply

Type conversion is always explicit

📖 Scenario: Imagine you are creating a simple calculator app that adds two numbers. The numbers come as strings from user input, but to add them, you need to convert these strings into numbers explicitly.

🎯 Goal: You will build a small Swift program that converts string values to integers explicitly and then adds them together.

📋 What You'll Learn

Create two string variables with exact values

Create an integer variable to hold the sum

Convert strings to integers explicitly using Int()

Add the converted integers

Print the sum

💡 Why This Matters

🌍 Real World

User input from text fields often comes as strings. To perform calculations, you must convert these strings explicitly to numbers.

💼 Career

Understanding explicit type conversion is essential for app development, data processing, and avoiding runtime errors in Swift programming.

1

Create two string variables

Create two string variables called firstNumber and secondNumber with the exact values "10" and "20" respectively.

Swift

# Your code here

Need a hint?

Use let to create constants for the strings.

2

Create an integer variable for the sum

Create an integer variable called sum and set it to 0.

Swift

let firstNumber = "10"
let secondNumber = "20"
// Your code here

Need a hint?

Use var because the value will change later.

3

Convert strings to integers and add

Convert firstNumber and secondNumber to integers explicitly using Int() and add them. Assign the result to sum. Use optional binding with if let to unwrap the converted values safely.

Swift

let firstNumber = "10"
let secondNumber = "20"
var sum = 0
// Your code here

Need a hint?

Use if let to safely convert strings to integers before adding.

4

Print the sum

Print the value of sum using print().

Swift

let firstNumber = "10"
let secondNumber = "20"
var sum = 0
if let num1 = Int(firstNumber), let num2 = Int(secondNumber) {
    sum = num1 + num2
}
// Your code here

Need a hint?

Use print(sum) to show the result.