Swift - Constants and Variables Quiz

Topics: Declaration, Type Annotation, Naming, and Printing

Swift Quiz #01: Constants and Variables

Constants and variables associate a name with a value of a particular type. Constants have values that cannot be changed, while variables can be reassigned to different values in the future.

4 mins read

1. What keyword is used to declare constants in Swift?

var

let

const

2. Are the below constants valid?

let 你好 = “你好世界”  
let 🐶🐮 = “dogcow”

Yes

3. What is the syntax for declaring multiple constants on a single line?

var x = 1, y = 1, z = 1

let x = 1, y = 1, z = 1

let x, y, z = 1

4. What is the purpose of providing a type annotation in Swift?

To specify the value of a constant or variable.

To indicate the type of values a constant or variable can store.

To make the code more readable.

5. What characters are not allowed in constant and variable names?

Whitespaces and mathematical symbols

Letters and numbers

Special characters and emojis

6. How do you print the current value of a constant or variable in Swift?

printValue()

print()

log()

7. What is the default terminator used by the `print()` function?

Line break

Space

Tab

8.
What is the purpose of string interpolation in Swift?
e.g print("current value of count is \(count)")

To print the name of a constant or variable

To include the value of a constant or variable in a string

To format strings in a specific way

9. Is the below variable declaration valid?

var `while` = 10

Yes

10. What happens if you try to change the value of a constant in Swift?

It compiles successfully and updates the value

It results in a compile-time error

It results in run-time error