Switch with where clauses in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of switch with where clause filtering

What is the output of this Swift code using a switch with a where clause?

Swift

let number = 15
switch number {
case let x where x % 3 == 0 && x % 5 == 0:
    print("FizzBuzz")
case let x where x % 3 == 0:
    print("Fizz")
case let x where x % 5 == 0:
    print("Buzz")
default:
    print(number)
}

A Fizz

B FizzBuzz

C Buzz

D 15

💡 Hint

Remember the order of cases and how where clauses filter values.

The number 15 is divisible by both 3 and 5, so the first case with where clause matching both conditions runs, printing "FizzBuzz".

❓ Predict Output

intermediate

Switch with multiple where clauses

What will this Swift code print?

Swift

let point = (x: 3, y: 4)
switch point {
case let (x, y) where x == y:
    print("On the diagonal")
case let (x, y) where x > y:
    print("Above the diagonal")
case let (x, y) where x < y:
    print("Below the diagonal")
default:
    print("Unknown")
}

A On the diagonal

B Above the diagonal

C Unknown

D Below the diagonal

💡 Hint

Compare x and y values carefully.

Since x=3 and y=4, x < y is true, so it prints "Below the diagonal".

🔧 Debug

advanced

Identify the error in switch with where clause

This Swift code does not compile. What is the error?

Swift

let value = 10
switch value {
case let x where x > 5:
    print("Greater than 5")
case let x where x <= 5:
    print("5 or less")
}

A Missing default case

B Cannot use let binding in switch cases

C Missing colon ':' after the first case's where clause

D Cannot use comparison operators in where clause

💡 Hint

Check punctuation after case statements.

The first case is missing a colon ':' after the where clause, causing a syntax error.

🚀 Application

advanced

Using switch with where to classify ages

Given this Swift code, what is the output?

Swift

let age = 20
switch age {
case let x where x >= 0 && x <= 12:
    print("Child")
case let x where x >= 13 && x <= 19:
    print("Teenager")
case let x where x >= 20 && x <= 64:
    print("Adult")
case let x where x >= 65:
    print("Senior")
default:
    print("Invalid age")
}

A Adult

B Teenager

C Senior

D Invalid age

💡 Hint

Check which age range 20 falls into.

Age 20 fits the third case where age is between 20 and 64, so it prints "Adult".

🧠 Conceptual

expert

Behavior of switch with overlapping where clauses

Consider this Swift code snippet. Which case will execute and why?

Swift

let number = 8
switch number {
case let x where x > 5:
    print("Greater than 5")
case let x where x > 3:
    print("Greater than 3")
default:
    print("3 or less")
}

A Prints "Greater than 5" because the first matching case is executed

B Prints "Greater than 3" because it is the more specific condition

C Prints "3 or less" because default always runs

D Compilation error due to overlapping where clauses

💡 Hint

Switch executes the first matching case only.

The switch stops at the first case where x > 5 is true (8 > 5), so it prints "Greater than 5" and does not check further cases.