Parameters with default values in Kotlin - Mini Project: Build & Apply

Parameters with Default Values in Kotlin

📖 Scenario: You are creating a simple greeting function for a friendly chatbot. Sometimes the chatbot knows the user's name, and sometimes it doesn't. You want the chatbot to greet the user by name if given, or use a general greeting if no name is provided.

🎯 Goal: Build a Kotlin function called greet that uses a parameter with a default value. This function will print a greeting message using the name if provided, or a default greeting if no name is given.

📋 What You'll Learn

Create a function named greet with a parameter name of type String that has a default value.

Set the default value of name to "Guest".

Inside the function, print a greeting message using the name parameter.

Call the greet function twice: once without any argument, and once with the argument "Alice".

💡 Why This Matters

🌍 Real World

Functions with default parameters are common in apps and programs to provide flexible behavior without forcing users to always give all details.

💼 Career

Understanding default parameters is important for writing clean, reusable code in Kotlin, which is widely used for Android app development and backend services.

1

Create the greet function with a name parameter

Write a Kotlin function called greet that has one parameter named name of type String. Set the default value of name to "Guest". Inside the function, write a print statement that prints "Hello, $name!" using string interpolation with println.

Kotlin

fun greet(name: String = "Guest") {
    // Your code here
}

Need a hint?

Use fun greet(name: String = "Guest") to create the function with a default parameter. Use println("Hello, $name!") to print the greeting.

2

Call greet without an argument

Call the greet function without passing any argument to use the default name.

Kotlin

fun greet(name: String = "Guest") {
    println("Hello, $name!")
}

// Call greet without argument
// Your code here

Need a hint?

Just write greet() to call the function without any argument.

3

Call greet with the argument "Alice"

Add a call to the greet function passing the argument "Alice" to greet Alice by name.

Kotlin

fun greet(name: String = "Guest") {
    println("Hello, $name!")
}

greet()

// Call greet with "Alice"
// Your code here

Need a hint?

Call the function with greet("Alice") to greet Alice.

4

Print the greetings

Run the program so it prints the greetings for the default name and for "Alice".

Kotlin

fun greet(name: String = "Guest") {
    println("Hello, $name!")
}

greet()
greet("Alice")

// Print greetings
// Your code here

Need a hint?

Just run the program. It should print two greetings: one for the default name and one for Alice.