Switch with value binding in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of switch with value binding and where clause

What is the output of this Swift code?

Swift

let point = (3, 4)
switch point {
case let (x, y) where x == y:
    print("On the line x == y")
case let (x, y) where x == -y:
    print("On the line x == -y")
case let (x, y):
    print("Somewhere else at (\(x), \(y))")
}

A On the line x == y

B On the line x == -y

C Somewhere else at (3, 4)

D No output

💡 Hint

Check the conditions in the where clauses carefully.

The point (3, 4) does not satisfy x == y or x == -y, so it matches the last case and prints the coordinates.

❓ Predict Output

intermediate

Switch with value binding and tuple pattern

What will this Swift code print?

Swift

let coordinate = (0, 5)
switch coordinate {
case (0, let y):
    print("On the y-axis at \(y)")
case (let x, 0):
    print("On the x-axis at \(x)")
case let (x, y):
    print("Somewhere else at (\(x), \(y))")
}

A On the x-axis at 0

B On the y-axis at 5

C Somewhere else at (0, 5)

D No output

💡 Hint

Look at the tuple pattern matching order.

The coordinate (0, 5) matches the first case where x is 0 and y is bound to 5.

🔧 Debug

advanced

Identify the error in switch with value binding

What error does this Swift code produce?

Swift

let number = 10
switch number {
case let x where x > 5:
    print("Greater than 5")
case let x where x < 5:
    print("Less than 5")
case let x where x == 5:
    print("Equal to 5")
}

A No error, prints 'Greater than 5'

B RuntimeError: No matching case found

C SyntaxError: Missing parentheses in where clause

D SyntaxError: Missing colon after case condition

💡 Hint

Check the syntax of each case line carefully.

The last case is missing a colon at the end of the case line, causing a syntax error.

❓ Predict Output

advanced

Switch with nested value binding and pattern matching

What is the output of this Swift code?

Swift

enum Result {
    case success(data: Int)
    case failure(error: String)
}

let result = Result.success(data: 42)
switch result {
case .success(let data) where data > 40:
    print("Big success with \(data)")
case .success(let data):
    print("Success with \(data)")
case .failure(let error):
    print("Failed with error: \(error)")
}

A Big success with 42

B Success with 42

C Failed with error: 42

D No output

💡 Hint

Check the where clause condition in the first case.

The result is a success with data 42, which is greater than 40, so the first case matches.

🧠 Conceptual

expert

Value binding behavior in switch cases

Consider this Swift code snippet. What will be the value of variable 'message' after execution?

Swift

let value = (2, 3)
var message = ""
switch value {
case let (x, y) where x == y:
    message = "Equal"
case let (x, y) where x > y:
    message = "X is greater"
case let (x, y):
    message = "X is less"
}

A "X is less"

B "X is greater"

C "Equal"

D "No match"

💡 Hint

Compare the values of x and y carefully.

Since 2 is less than 3, the last case matches and message is set to "X is less".