Unit type as void equivalent in Kotlin - Mini Project: Build & Apply

Unit Type as Void Equivalent in Kotlin

📖 Scenario: Imagine you are creating a simple Kotlin program that performs actions without returning any value, similar to how void works in other languages.

🎯 Goal: You will learn how to use Kotlin's Unit type as the equivalent of void by creating functions that do not return any value and calling them.

📋 What You'll Learn

Create a function with return type Unit

Create a function without explicitly specifying return type that returns Unit

Call both functions

Print messages inside the functions to show they are executed

💡 Why This Matters

🌍 Real World

Many Kotlin programs use <code>Unit</code> functions for actions like printing, logging, or updating UI where no return value is needed.

💼 Career

Understanding <code>Unit</code> helps you read and write Kotlin code clearly, especially when working with functions that perform tasks without returning data.

1

Create a function with return type Unit

Write a function called printHello that returns Unit and prints the message "Hello from printHello" inside it.

Kotlin

// Write the function printHello with return type Unit
// Your code here

Need a hint?

Remember, Unit is the Kotlin equivalent of void. You can specify it explicitly as the return type.

2

Create a function without explicit return type (Unit inferred)

Write a function called printWorld that does not specify a return type but prints the message "Hello from printWorld" inside it.

Kotlin

fun printHello(): Unit {
    println("Hello from printHello")
}

// Write the function printWorld without explicit return type
// Your code here

Need a hint?

If you don't specify a return type, Kotlin assumes Unit for functions without a return value.

3

Call both functions

Call the functions printHello() and printWorld() in the main function.

Kotlin

fun printHello(): Unit {
    println("Hello from printHello")
}

fun printWorld() {
    println("Hello from printWorld")
}

fun main() {
    // Call printHello and printWorld here
    // Your code here
}

Need a hint?

Inside main, just write the function calls on separate lines.

4

Print the output of calling the functions

Run the program and observe the printed output from calling printHello() and printWorld(). The output should show both messages.

Kotlin

fun printHello(): Unit {
    println("Hello from printHello")
}

fun printWorld() {
    println("Hello from printWorld")
}

fun main() {
    printHello()
    printWorld()
    // Observe the output
    // Your code here
}

Need a hint?

When you run the program, you should see both messages printed on separate lines.