Welcome to the world of Swift programming! Swift is a powerful and intuitive programming language developed by Apple for building apps for iOS, macOS, watchOS, and tvOS. This module will introduce you to the basics of Swift, setting a strong foundation for your journey in app development.

Swift is a modern programming language that is:

• Safe: Swift eliminates entire classes of unsafe code.
• Fast: Swift is designed to be fast and efficient.
• Expressive: Swift syntax is concise yet expressive, making it easier to read and write.

Before we dive into coding, ensure you have Xcode installed on your Mac. Xcode is the integrated development environment (IDE) for Swift and other Apple programming languages.

1. Open the App Store on your Mac.
2. Search for Xcode.
3. Click Get and then Install.
4. Once installed, open Xcode and create a new playground to start experimenting with Swift.

Let's start with a simple "Hello, World!" program. This is a traditional first program that prints "Hello, World!" to the console.

• import Foundation: This line imports the Foundation framework, which provides essential data types, collections, and operating-system services.
• print("Hello, World!"): This function prints the string "Hello, World!" to the console.

In Swift, you use var to declare variables and let to declare constants.

Code Example:

Explanation:

• var myVariable = 42: Declares a variable named myVariable with an initial value of 42.
• let myConstant = 3.14: Declares a constant named myConstant with a value of 3.14.

Swift is a type-safe language, meaning it ensures that variables are used consistently with their declared types.

Common Data Types:

• Int: Integer numbers
• Double and Float: Floating-point numbers
• String: Text
• Bool: Boolean values (true or false)

Code Example:

Comments are used to annotate code and are ignored by the compiler.

Single-line Comment:

Multi-line Comment:

1. Create a new playground in Xcode.
2. Declare a variable named age and assign it your age.
3. Declare a constant named pi and assign it the value of π (3.14159).
4. Print both values to the console.

Solution:

1. Declare a variable named temperature of type Double and assign it a value.
2. Declare a constant named greeting of type String and assign it a value.
3. Print both values to the console.

Solution:

• Type Mismatch: Assigning a value of the wrong type to a variable or constant.
  • Example: var number: Int = "Hello" (This will cause an error because "Hello" is a String, not an Int).
• Using var instead of let: Use let for values that do not change to avoid accidental modifications.

• Use Descriptive Names: Choose variable and constant names that clearly describe their purpose.
• Consistent Formatting: Follow consistent formatting and indentation to make your code more readable.

In this lesson, you have learned the basics of Swift programming, including how to declare variables and constants, use different data types, and write simple programs. These fundamentals are crucial as you progress through the course and start building more complex applications.

Next, we will dive deeper into variables and constants, exploring their usage and best practices in more detail. Happy coding!