Bool type and logical operators in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Swift code using logical AND?

Consider the following Swift code snippet. What will be printed when it runs?

Swift

let a = true
let b = false
print(a && b)

A false

B true

C nil

D Compilation error

💡 Hint

Remember that logical AND (&&) returns true only if both sides are true.

The logical AND operator returns true only if both operands are true. Here, 'a' is true but 'b' is false, so the result is false.

❓ Predict Output

intermediate

What does this Swift code print using logical OR?

Look at this Swift code. What will be the output?

Swift

let x = false
let y = true
print(x || y)

A true

B false

C nil

D Runtime error

💡 Hint

Logical OR (||) returns true if at least one operand is true.

Since 'y' is true, the OR operation returns true regardless of 'x'.

❓ Predict Output

advanced

What is the output of this Swift code with combined logical operators?

Analyze this Swift code and determine what it prints.

Swift

let p = true
let q = false
let r = true
print(p && q || r)

A Compilation error

B false

C true

D nil

💡 Hint

Remember the precedence: && is evaluated before ||.

First, p && q is false (true && false = false). Then false || r is true (false || true = true).

❓ Predict Output

advanced

What does this Swift code print using the NOT operator?

What is the output of this Swift code snippet?

Swift

let flag = false
print(!flag)

A false

B Syntax error

C nil

D true

💡 Hint

The NOT operator (!) reverses the Boolean value.

Since flag is false, !flag is true.

🧠 Conceptual

expert

How many items are in the resulting dictionary after this Swift code runs?

Consider this Swift code that uses Boolean keys in a dictionary. How many key-value pairs does the dictionary contain after execution?

Swift

var dict = [Bool: String]()
dict[true] = "Yes"
dict[false] = "No"
dict[true] = "Maybe"

A 1

B 2

C 3

D 0

💡 Hint

Dictionary keys must be unique. Assigning a value to an existing key replaces the old value.

The dictionary has two keys: true and false. The value for true is updated from "Yes" to "Maybe", so total pairs remain 2.