Understanding Swift Return Statement

In Swift, the return statement is used to exit from a function and optionally provide a value back to the caller. It plays a crucial role in controlling the flow of execution and ensuring functions produce the expected results.

A function in Swift can either return a value or return nothing (denoted by Void or simply omitting the return type). When a function has a return type, using return becomes mandatory to provide the expected result.

Key Points to Remember

The return statement immediately exits the function and transfers control back to the caller.
If a function specifies a return type, it must return a value of that type.
A function with a Void return type can omit the return statement or use it alone to exit early.
Multiple return statements can be used in conditional branches within a function.

Syntax

func functionName(parameters) -> ReturnType {
return value
}

If the function has no return type:

func functionName(parameters) {
return // Optional in Void functions
}

Example 1: Returning a String Value

Let's demonstrate how a function can return a string in Swift.

import Foundation

func greet(name: String) -> String {
return "Hello, \(name)!"
}

let message = greet(name: "Alice")
print(message)

Output

Hello, Alice!

Example 2: Returning an Integer Value

import Foundation

func square(of number: Int) -> Int {
return number * number
}

let result = square(of: 5)
print("Square: \(result)")

Output

Square: 25

Example 3: Early Return in a Function

You can use the return statement to exit a function early based on a condition.

import Foundation

func checkEvenOrOdd(_ number: Int) -> String {
if number % 2 == 0 {
return "Even"
}
return "Odd"
}

print(checkEvenOrOdd(7))

Output

Odd