Int, Double, Float number types in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Swift code with mixed number types?

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

Swift

let a: Int = 5
let b: Double = 3.2
let c = Double(a) + b
print(c)

A 8.2

B 8

C Type error at compile time

D 5.32

💡 Hint

Remember that you need to convert Int to Double before adding.

The Int value 5 is converted to Double 5.0, then added to 3.2, resulting in 8.2.

❓ Predict Output

intermediate

What is the value of variable 'result' after this Swift code runs?

Look at this Swift code. What is the value of 'result'?

Swift

let x: Float = 2.5
let y: Double = 4.5
let result = Double(x) * y
print(result)

A Type mismatch error

B 11.25f

C 7.0

D 11.25

💡 Hint

Float must be converted to Double before multiplication.

Float 2.5 is converted to Double 2.5, multiplied by 4.5, resulting in 11.25.

❓ Predict Output

advanced

What error does this Swift code produce?

Examine this Swift code snippet. What error will it cause when compiled?

Swift

let a: Int = 10
let b: Float = 3.5
let c = a + b
print(c)

A Prints 13.5

B Prints 13

C Type error: Cannot add Int and Float directly

D Runtime error: nil value

💡 Hint

Swift does not allow adding Int and Float without conversion.

You must convert either Int to Float or Float to Int before adding; otherwise, compiler error occurs.

🧠 Conceptual

advanced

Which Swift type is best for precise decimal calculations?

You want to store currency values in Swift with exact decimal precision. Which type should you use?

A Float

B Decimal

C Int

D Double

💡 Hint

Floating point types can cause rounding errors.

Decimal type is designed for precise decimal arithmetic, ideal for currency.

❓ Predict Output

expert

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

Analyze this Swift code and determine the number of elements in 'results'.

Swift

let numbers: [Double] = [1.0, 2.5, 3.7, 4.0]
let results = numbers.compactMap { num -> Int? in
    let intValue = Int(num)
    return num == Double(intValue) ? intValue : nil
}
print(results.count)

A 2

B 3

C 1

D 4

💡 Hint

compactMap filters out nil values after checking if Double equals Int conversion.

Only 1.0 and 4.0 are whole numbers; 2.5 and 3.7 are filtered out, so count is 2.