Swift Control flow Quiz

Test your understanding of Swift Control flow by taking this Quiz

Swift Quiz #07 - Swift Control flow

Test your understanding of Swift Control flow by taking this Quiz

5 mins read

1. What value does the function calculate() return?

  func calculate() -> Int {
      var result = 0
      for i in 1...5 {
          if i % 2 == 0 {
              result += i
          } else {
              result -= i
          }
      }
      return result
  }

-3

2. Which of the following control flow statements in Swift can be used to exit the current iteration of a loop?

break

continue

return

All of the above

3. What is the output?

 func printNames() {
     let names = ["John", "Amy", "Emily", "Michael"]
     for name in names {
         if name == "Amy" {
             continue
         }
         print(name)
         if name == "Emily" {
             break
         }
     }
 }

John

John Emily

John Amy Emily

John Amy Emily Michael

4. What is the primary difference between the `if` and `guard` statements in Swift?

`if` for early exit, while the `guard` is for condition checking.

`if` for multiple conditions checking, while the `guard` for optional unwrapping.

`if` must have an `else`, while `guard` need not.

`if` can be used in any scope, while the `guard` can only be used in functions or methods.

5. What is the output?

 func calc() {
     defer {
         print("Step 3")
     }
     print("Step 1")
     defer {
         print("Step 4")
     }
     print("Step 2")
 }

Step 1 Step 2 Step 3 Step 4

Step 1 Step 2 Step 4 Step 3

Step 2 Step 1 Step 3 Step 4

Step 2 Step 1 Step 4 Step 3

6. What is the output?

 func calc() -> Int {
     var x = 10
     repeat {
         x += 5
     } while x < 30
     return x
 }

7. What is the output when executed on iOS 16?

 func checkOS() {
     let condition = false
     if #available(iOS 14, *) {
         print("Running on iOS 14 or later")
     } else {
         print("Running on earlier iOS version")
     }
 }

Running on iOS 14 or later

Running on earlier iOS version

8. What is the output?

 func printChars() -> String {
     var result = ""
     for i in 1...3 {
         switch i {
         case 1, 3:
             result += "A"
         case 2:
             result += "B"
         default:
             result += "C"
         }
     }
     return result
 }

ABC

ABA

9. What is the output?

func example() {
     var x = 10
     defer {
         x += 5
     }
     if x > 5 {
         print(x)
         return
     }
     print(x - 5)
 }