Switch with compound cases in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to match multiple cases in one line.

Swift

let fruit = "apple"
switch fruit {
    case [1]:
        print("It's a citrus fruit.")
    default:
        print("It's another fruit.")
}

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

A"grape", "melon"

B"orange", "lemon"

C"orange", "lemon", "lime"

D"apple", "banana"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to separate values with commas.

Using parentheses instead of commas.

Not enclosing strings in quotes.

In Swift, you can match multiple values in a single case by separating them with commas inside the case statement.

2fill in blank

medium

Complete the switch statement to print "Weekend" for Saturday and Sunday.

Swift

let day = "Sunday"
switch day {
    case [1]:
        print("Weekend")
    default:
        print("Weekday")
}

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

A"Friday", "Saturday"

B"Monday", "Tuesday"

C"Sunday", "Monday"

D"Saturday", "Sunday"

Attempts:

3 left

💡 Hint

Common Mistakes

Including weekdays in the weekend case.

Forgetting to use commas between days.

Not enclosing day names in quotes.

Saturday and Sunday are weekend days, so they should be grouped in the same case separated by commas.

3fill in blank

hard

Fix the error in the switch case to correctly match multiple values.

Swift

let number = 3
switch number {
    case [1]:
        print("Number is 1, 2, or 3")
    default:
        print("Other number")
}

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

A1, 2, 3

B1 || 2 || 3

C[1, 2, 3]

D1 && 2 && 3

Attempts:

3 left

💡 Hint

Common Mistakes

Using logical OR (||) instead of commas.

Using array brackets [] in case.

Using logical AND (&&) instead of commas.

In Swift switch cases, multiple values are separated by commas, not logical operators or array brackets.

4fill in blank

hard

Fill both blanks to create a switch that prints "Vowel" for 'a', 'e', 'i', 'o', 'u' and "Consonant" for 'b', 'c', 'd'.

Swift

let letter: Character = "a"
switch letter {
    case [1]:
        print("Vowel")
    case [2]:
        print("Consonant")
    default:
        print("Other letter")
}

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

A'a', 'e', 'i', 'o', 'u'

B'a', 'e', 'i'

C'b', 'c', 'd'

D'x', 'y', 'z'

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing vowels and consonants in the same case.

Using parentheses instead of commas.

Not enclosing characters in single quotes.

The first case matches vowels separated by commas; the second case matches consonants similarly.

5fill in blank

hard

Fill all three blanks to create a switch that prints "Small", "Medium", or "Large" for sizes 1-2, 3-4, and 5-6 respectively.

Swift

let size = 4
switch size {
    case [1]:
        print("Small")
    case [2]:
        print("Medium")
    case [3]:
        print("Large")
    default:
        print("Unknown size")
}

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

A1, 2

B3, 4

C5, 6

D7, 8

Attempts:

3 left

💡 Hint

Common Mistakes

Using ranges like 1...2 instead of listing values separated by commas.

Mixing sizes between cases.

Not separating values with commas.

Each case matches a range of sizes separated by commas to group them correctly.

Practice

1.

What does a compound case in a Swift switch statement allow you to do?

easy

A. Skip the default case safely

B. Use multiple switch statements at once

C. Combine if and switch in one line

D. Match multiple values in a single case using commas

Solution

1. Step 1: Understand compound cases

   Compound cases let you list several values separated by commas in one case.

2. Step 2: Recognize the benefit

   This makes the code cleaner by avoiding repeated code for similar cases.

3. Final Answer:

   Match multiple values in a single case using commas -> Option D

4. Quick Check:

   Compound case = multiple values in one case [OK]

Hint: Look for commas inside a case to spot compound cases [OK]

Common Mistakes:

• Thinking compound cases combine multiple switches
• Believing compound cases skip default
• Confusing compound cases with if-else

2.

Which of the following is the correct syntax for a compound case in Swift?

switch value {
    case 1, 2, 3:
        print("One to three")
    default:
        print("Other")
}

easy

A. case 1, 2, 3:

B. case 1; 2; 3:

C. case (1, 2, 3):

D. case [1, 2, 3]:

Solution

1. Step 1: Recall Swift compound case syntax

   Swift uses commas to separate multiple values in one case.

2. Step 2: Check each option

   case 1, 2, 3: uses commas correctly; others use semicolons, parentheses, or brackets incorrectly.

3. Final Answer:

   case 1, 2, 3: -> Option A

4. Quick Check:

   Commas separate values in compound case [OK]

Hint: Use commas, not semicolons or brackets, for compound cases [OK]

Common Mistakes:

• Using semicolons instead of commas
• Putting values inside parentheses or brackets
• Missing the colon after case

3.

What will be printed by this Swift code?

let letter = "b"
switch letter {
case "a", "e", "i", "o", "u":
    print("Vowel")
case "b", "c", "d":
    print("Consonant")
default:
    print("Other")
}

medium

A. Vowel

B. No output

C. Consonant

D. Other

Solution

1. Step 1: Identify the value of letter

   The variable letter is "b".

2. Step 2: Match letter in switch cases

   "b" matches the second case with "b", "c", "d" which prints "Consonant".

3. Final Answer:

   Consonant -> Option C

4. Quick Check:

   "b" in second case = Consonant [OK]

Hint: Check which case list contains the value [OK]

Common Mistakes:

• Confusing vowels and consonants
• Forgetting to include default case
• Assuming no output if no exact match

4.

Find the error in this Swift switch statement:

let number = 3
switch number {
case 1, 2
    print("One or Two")
case 3:
    print("Three")
default:
    print("Other")
}

medium

A. Missing colon after case 1, 2

B. Missing default case

C. Cannot use compound cases with integers

D. Missing parentheses around 1, 2

Solution

1. Step 1: Check syntax of each case

   Each case must end with a colon (:). The first case is missing it.

2. Step 2: Verify other parts

   Default case is present; compound cases with integers are allowed; parentheses are not needed.

3. Final Answer:

   Missing colon after case 1, 2 -> Option A

4. Quick Check:

   Case lines must end with colon [OK]

Hint: Look for missing colons after case labels [OK]

Common Mistakes:

• Forgetting colon after case
• Thinking parentheses are required
• Believing compound cases disallow integers

5.

Given this Swift code, what will be the output?

let grade = "B"
switch grade {
case "A", "B", "C":
    print("Pass")
case "D", "F":
    print("Fail")
case "I", "W":
    print("Incomplete or Withdrawn")
default:
    print("Unknown grade")
}

hard

A. Incomplete or Withdrawn

B. Pass

C. Fail

D. Unknown grade

Solution

1. Step 1: Identify the value of grade

   The variable grade is "B".

2. Step 2: Match grade in compound cases

   "B" matches the first case "A", "B", "C" which prints "Pass".

3. Final Answer:

   Pass -> Option B

4. Quick Check:

   "B" in first case = Pass [OK]

Hint: Match value to any in compound case list [OK]

Common Mistakes:

• Assuming "B" is a fail grade
• Ignoring default case
• Confusing case groups