[Swift Apple ] 5. Swift calculations , Swift match | how to use numbers in Swift coding | Swift integer, Swift Decimal

🔢 5. Numbers and Calculations

Hello there! 😊 Today, we’re going to learn how to use numbers in Swift coding.

We’ll talk about integers, decimals, and how to do basic math operations like addition and subtraction.

And at the end, we’ll even build a simple age calculator together! 🚀

🔢 What’s the Difference Between Int and Double?

In Swift, there are two main types of numbers:

Type	What It Means	Example Values	Swift Type
Integer	Whole numbers (no dots)	3, 10, -5	Int
Decimal	Numbers with dots	3.14, -2.5	Double

Example:

var age: Int = 10
var pi: Double = 3.14

Use Int when you’re working with whole numbers,

and Double when you need decimal points (like in math or science).

➕➖✖️➗ Doing Math in Swift

Swift makes it easy to do basic math just like in school:

Operation	Symbol	Example Code	Result
Addition	+	2 + 3	5
Subtraction	-	10 - 4	6
Multiplication	*	3 * 5	15
Division	/	10 / 2	5

Sample Code:

let a = 10
let b = 4

print(a + b)  // 14
print(a - b)  // 6
print(a * b)  // 40
print(a / b)  // 2

Note: If you divide two Int numbers, the result will also be an Int (no decimals).

For example: 9 / 2 will give you 4 instead of 4.5.

🧪 Practice: Build an Age Calculator

Now it’s time to write your own code!

Let’s build a simple age calculator.

let birthYear = 2014
let thisYear = 2025

let age = thisYear - birthYear
print("You are \(age) years old.")

Output:

You are 11 years old.

Try changing the birthYear and see how the result changes! 😄

💡 Bonus: Life Expectancy Calculator

Want a little challenge?

Let’s say the average life expectancy is 100 years.

You can also calculate how many years you have left!

let lifeExpectancy = 100
let remaining = lifeExpectancy - age

print("You might have \(remaining) more years to live!")

This is a fun way to mix math with real-world ideas.

✨ Wrapping Up

Today, we learned how to use numbers in Swift:

• Int = whole numbers

• Double = decimal numbers

• Math operations: +, -, *, /

• We built a simple age calculator! 🎉

In the next lesson, we’ll learn how to work with letters and sentences in Swift.

It’s called: ✉️ Letters and Words!

See you next time on our Swift coding journey! 😊🚀