Comparison operators in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of chained comparison operators

What is the output of this Swift code snippet?

Swift

let a = 5
let b = 10
let c = 15
print(a < b && b < c)

A true

B false

C Compilation error

D Runtime error

💡 Hint

Think about how logical AND works with comparison operators.

The expression checks if a is less than b AND b is less than c. Both are true, so the result is true.

❓ Predict Output

intermediate

Result of equality and inequality operators

What will be printed by this Swift code?

Swift

let x = 7
let y = 7
print(x == y, x != y)

A true false

B false true

C true true

D false false

💡 Hint

Check if x and y are equal or not.

x == y is true because both are 7; x != y is false because they are equal.

❓ Predict Output

advanced

Output of mixed comparison and logical operators

What is the output of this Swift code?

Swift

let p = 3
let q = 6
let r = 9
print(p < q || q > r && r == 9)

A Runtime error

B false

C Compilation error

D true

💡 Hint

Remember operator precedence: && before ||.

q > r && r == 9 is false && true = false; p < q || false = true || false = true.

❓ Predict Output

advanced

Output of comparing optional values

What will this Swift code print?

Swift

let a: Int? = nil
let b: Int? = 5
print(a == b)

A Compilation error

B false

C true

D Runtime error

💡 Hint

Comparing nil to a value returns false.

Optional values can be compared; nil is not equal to 5, so false is printed.

❓ Predict Output

expert

Output of custom Comparable struct comparison

Given this Swift code, what is the output?

Swift

struct Box: Comparable {
    let volume: Int
    static func < (lhs: Box, rhs: Box) -> Bool {
        lhs.volume < rhs.volume
    }
}
let box1 = Box(volume: 10)
let box2 = Box(volume: 20)
print(box1 > box2)

A true

B Runtime error

C false

D Compilation error

💡 Hint

The > operator uses the < operator logic reversed.

box1.volume (10) is not greater than box2.volume (20), so false is printed.