In Swift, fallthrough is a keyword used within a switch statement to specify that control flow should continue to the next case label after the current one, even if the condition for the current case is satisfied. It essentially allows you to create a fallthrough behavior from one case to another.

Here's an example to illustrate how fallthrough works in Swift:

let number = 2

switch number {
case 1:
fallthrough // Control flow continues to the next case
case 2:

In this example, if number is 2, the output will be:


Even though the condition for the first case (1) is satisfied, the fallthrough keyword is used, so control flow continues to the next case (2). Without fallthrough, the execution would have stopped after "Two."

It's important to use fallthrough judiciously because it can lead to unexpected behavior if not used carefully. It's often used when you want to handle multiple cases in a similar way or when you want to create a cascading effect for certain conditions.