Matua Doc

Matua Doc

Swift functions: no parameters

Goal

Learn how to write and call a simple Swift function.

  • Focus on functions with no parameters and no return value.
  • Understand why these small functions make code clearer.
func showWelcome() {
    print("Welcome")
}

showWelcome()

What is a function with no parameters?

It is a named block of code that runs the same way every time.

  • Because it takes no input, it relies on internal logic or constants.
  • It is often used for simple actions like printing a title.
func printTitle() {
    print("Room calculator")
}

Why developers use functions

Functions reduce repetition by grouping steps into one name.

  • They improve readability because the name describes the action.
  • They make updates safer because changes happen in one place.
func printDivider() {
    print("------------")
}

printDivider()
printDivider()

Example of a no-parameter function

This function prints two lines of introduction text.

  • It shows how multiple steps can be wrapped in one name.
func printRoomIntro() {
    print("This program calculates room area.")
    print("It also calculates room volume.")
}

Anatomy of a function

The keyword func starts the definition.

  • The function name describes the action.
  • Empty parentheses mean there are no parameters.
  • Curly braces contain the body of the function.
func showWelcome() {
    print("Welcome to the room calculator")
}

How to write a no-parameter function

Choose a short verb-based name that describes the action.

  • Write the steps inside the braces in the correct order.
  • Keep the function focused on one clear task.
func printSummaryHeader() {
    print("Summary")
    print("-------")
}

How to use a no-parameter function in your code

Defining a function does not run it.

  • Call it by name with parentheses to execute the steps.
  • Place the call where you need the action to happen.
printSummaryHeader()
// more output here
printSummaryHeader()

How a no-parameter function contributes to flexibility

It lets you reuse the same output or setup in multiple places.

  • Changing the function updates every place it is called.
  • It makes long programs easier to scan and navigate.
func printNewSection() {
    print("\n--- New calculation ---")
}

printNewSection()
printNewSection()

How to test that a no-parameter function works properly in your code

Call the function once and check the output.

  • Call it twice to ensure repeated use is consistent.
  • Compare the output to the expected text.
func showWelcome() {
    print("Welcome")
}

showWelcome()
showWelcome()

Task A

Create a function called printRoomIntro().

  • Print two lines that explain the program’s purpose.
  • Call the function at the start of your program.
 
func printRoomIntro() {
    print("This program calculates room area and volume.")
    print("It also finds the usable space after furniture.")
}

printRoomIntro()

Task B

Create a function called printDivider().

  • Print a line of dashes.
  • Call it before and after your summary output.
 
func printDivider() {
    print("--------")
}

printDivider()
print("Summary here")
printDivider()

Task C

Create a function called printUnitsNote().

  • Print a note that measurements are in metres.
  • Call it before you show any calculations.
 
func printUnitsNote() {
    print("All measurements are in metres.")
}

printUnitsNote()

Task D

Create a function called printGoodbye().

  • Print a short closing message.
  • Call it at the end of the program.
 
func printGoodbye() {
    print("Done. Thanks for using the calculator.")
}

printGoodbye()