Switch with compound cases in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of switch with multiple values in one case

What is the output of this Swift code?

Swift

let number = 3
switch number {
case 1, 3, 5:
    print("Odd number")
case 2, 4, 6:
    print("Even number")
default:
    print("Unknown")
}

A Odd number

B Compilation error

C Unknown

D Even number

💡 Hint

Check which case matches the value 3 in the switch statement.

The value 3 matches the first case which includes 1, 3, and 5, so it prints "Odd number".

❓ Predict Output

intermediate

Switch with range and multiple values

What will this Swift code print?

Swift

let score = 85
switch score {
case 0, 1..<50:
    print("Fail")
case 50..<80, 80:
    print("Pass")
case 81...100:
    print("Excellent")
default:
    print("Invalid score")
}

A Invalid score

B Pass

C Fail

D Excellent

💡 Hint

Look carefully at the ranges and values in each case.

The score 85 falls in the range 81...100, so it prints "Excellent".

🔧 Debug

advanced

Identify the error in compound case syntax

Which option shows the correct way to write a compound case with ranges in Swift?

Swift

let value = 7
switch value {
case 1...5, 6...10:
    print("Within range")
default:
    print("Out of range")
}

A case 1...5; 6...10: print("Within range")

B case 1...5 6...10: print("Within range")

C case 1...5, 6...10: print("Within range")

D case 1...5 && 6...10: print("Within range")

💡 Hint

Compound cases are separated by commas, not spaces or other symbols.

Only option C uses the correct comma to separate multiple patterns in one case.

❓ Predict Output

advanced

Switch with tuple and compound cases

What is the output of this Swift code?

Swift

let point = (2, 3)
switch point {
case (0, 0), (1, 1):
    print("Origin or near origin")
case (2, 3), (3, 2):
    print("Close to (2,3)")
default:
    print("Somewhere else")
}

A Close to (2,3)

B Origin or near origin

C Somewhere else

D Compilation error

💡 Hint

Check which tuple matches the value (2, 3).

The tuple (2, 3) matches the second case, so it prints "Close to (2,3)".

❓ Predict Output

expert

Switch with where clause and compound cases

What will this Swift code print?

Swift

let number = 15
switch number {
case let x where x % 3 == 0 || x % 5 == 0:
    print("Divisible by 3 or 5")
default:
    print("Not divisible by 3 or 5")
}

A Not divisible by 3 or 5

B Divisible by 3 or 5

C Compilation error

D Runtime error

💡 Hint

Check if 15 is divisible by 3 or 5.

15 is divisible by both 3 and 5, so the first case matches and prints "Divisible by 3 or 5".

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