MasterOnce
HomeBlogHow-To
← Back to How-To
3 min readJan 23, 2026
Swift

How to Define and Call Functions

Extract logic into reusable functions.

Steps

  1. Paste the code into a Swift file or playground.
  2. Run it once to verify the output.
  3. Adjust the inputs to match your use case.

Copy and paste

import Foundation

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

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

Notes

  • Keep functions small and focused for reuse.
  • Prefer safe APIs like optionals and guards.