Swift Variables and Constants

What are Variables and Constants?

In Swift, variables and constants are the building blocks of your code. They store information that your program can use and manipulate. But how are they different?

Variables: Your Flexible Friend

Variables in Swift are declared using the var keyword. Think of variables as containers that can hold different values over time. Here’s how you define a variable:

var playerName = "Alex"

Here, playerName is a variable that currently holds the value "Alex". But the beauty of variables is that they can change, like this:

playerName = "Jordan"

Now, the playerName has a new value: "Jordan".

Constants: Unchanging and Reliable

Constants, on the other hand, are declared with the let keyword and are used to store values that never change. Once set, a constant’s value is fixed. Here’s how you create a constant:

let pi = 3.14159

Trying to change the value of pi later in your code will result in an error because pi is a constant.

Why Use Constants and Variables?

Understanding when to use constants and variables is key to writing clean, efficient, and error-free code in Swift:

• Use a Variable: When you expect the value to change, like a player’s score in a game.
• Use a Constant: When the value should remain the same throughout the program, like the number of days in a week.

Real-World Example: Planning a Party

Let’s put constants and variables into a real-world context: planning a party.

var guests = 10
let venue = "Rooftop Cafe"

Here, guests is a variable because the number of guests might change. But venue is a constant since the party location is fixed.