Data types (Int, Double, String, Bool) in iOS Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an integer variable named count with value 10.

iOS Swift

var count: [1] = 10

Drag options to blanks, or click blank then click option'

AInt

BBool

CString

DDouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using Double instead of Int for whole numbers.

Using String when a number is needed.

The type Int is used for whole numbers in Swift.

2fill in blank

medium

Complete the code to declare a variable price with a decimal value 9.99.

iOS Swift

var price: [1] = 9.99

Drag options to blanks, or click blank then click option'

ADouble

BBool

CInt

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Using Int for decimal numbers causes errors.

Using Bool or String instead of a number type.

The type Double is used for decimal numbers in Swift.

3fill in blank

hard

Fix the error in the code by choosing the correct type for the variable isActive.

iOS Swift

var isActive: [1] = true

Drag options to blanks, or click blank then click option'

AInt

BBool

CDouble

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Using String or Int for boolean values.

Using Double instead of Bool.

The type Bool is used for true or false values in Swift.

4fill in blank

hard

Fill both blanks to declare a variable greeting with a text value.

iOS Swift

var greeting: [1] = [2]

Drag options to blanks, or click blank then click option'

AString

B"Hello"

CBool

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes around text values.

Using Bool or Int types for text.

The type String is used for text. Text values must be in quotes.

5fill in blank

hard

Fill all three blanks to declare a variable temperature with a decimal value and print it.

iOS Swift

var [1]: [2] = [3]
print(temperature)

Drag options to blanks, or click blank then click option'

Atemperature

BDouble

C36.6

DInt

Attempts:

3 left

💡 Hint

Common Mistakes

Using Int instead of Double for decimal values.

Using wrong variable name.

Declare a variable named temperature of type Double with value 36.6. Then print it.

Practice

1. Which Swift data type is used to store true or false values?

easy

A. Int

B. Double

C. String

D. Bool

Solution

1. Step 1: Understand the data types

   Bool stores true or false values, Int stores whole numbers, String stores text, and Double stores decimal numbers.

2. Step 2: Match the description to the type

   Since the question asks for true or false values, the correct type is Bool.

3. Final Answer:

   Bool -> Option D

4. Quick Check:

   Bool = true/false [OK]

Hint: True/false values always use Bool type [OK]

Common Mistakes:

• Confusing Bool with Int
• Using String for true/false
• Choosing Double for boolean values

2. Which of the following is the correct way to declare a Double variable named price with value 9.99 in Swift?

easy

A. var price: Double = 9.99

B. var price = "9.99"

C. var price Double = 9.99

D. var price: Int = 9.99

Solution

1. Step 1: Check variable declaration syntax

   In Swift, to declare a variable with a specific type, use var name: Type = value.

2. Step 2: Identify the correct type and value

   Since 9.99 is a decimal number, the type must be Double. var price: Double = 9.99 correctly declares price as Double with 9.99.

3. Final Answer:

   var price: Double = 9.99 -> Option A

4. Quick Check:

   Double declaration uses var name: Double = value [OK]

Hint: Use var name: Double = value for decimals [OK]

Common Mistakes:

• Assigning decimal to Int
• Using quotes for numbers
• Omitting type when needed

3. What will be the output of this Swift code?

let number: Int = 5
let text: String = "5"
let isEqual = (number == Int(text)!)
print(isEqual)

medium

A. true

B. false

C. 5

D. Compilation error

Solution

1. Step 1: Understand the code logic

   number is an Int with value 5, text is a String "5". Int(text) converts the string "5" to integer 5.

2. Step 2: Compare values

   number == Int(text) compares 5 == 5, which is true. So isEqual is true and print outputs true.

3. Final Answer:

   true -> Option A

4. Quick Check:

   5 == 5 is true [OK]

Hint: Convert String to Int before comparing [OK]

Common Mistakes:

• Comparing Int and String directly
• Forgetting Int(text) conversion
• Expecting string output

4. Identify the error in this Swift code snippet:

var isActive: Bool = "true"
print(isActive)

medium

A. print() cannot print Bool values

B. Bool cannot be assigned a String value

C. Variable name is invalid

D. Missing semicolon at end of line

Solution

1. Step 1: Analyze variable assignment

   isActive is declared as Bool but assigned the string "true" (in quotes), which is incorrect.

2. Step 2: Understand type mismatch

   Bool must be assigned true or false without quotes. Assigning a String causes a type error.

3. Final Answer:

   Bool cannot be assigned a String value -> Option B

4. Quick Check:

   Bool = true/false only, no quotes [OK]

Hint: Bool values are true or false without quotes [OK]

Common Mistakes:

• Using quotes around true/false
• Expecting semicolon error
• Thinking print can't show Bool

5. You want to store a user's age, height in meters, full name, and whether they are a student. Which Swift data types should you use for these variables respectively?

hard

A. String, String, Int, Bool

B. Double, Int, Bool, String

C. Int, Double, String, Bool

D. Bool, Int, Double, String

Solution

1. Step 1: Match each data to its type

   Age is a whole number -> Int, height with decimals -> Double, full name is text -> String, student status true/false -> Bool.

2. Step 2: Verify option matches order

   Int, Double, String, Bool lists Int, Double, String, Bool in that order, matching the variables correctly.

3. Final Answer:

   Int, Double, String, Bool -> Option C

4. Quick Check:

   Whole number, decimal, text, true/false [OK]

Hint: Match data meaning: whole, decimal, text, true/false [OK]

Common Mistakes:

• Mixing Int and Double
• Using Bool for text
• Confusing order of types