Unable to initialize kotlin class member from secondary function

• Property must be initialized or be abstract:

You got this error because you didn't initialize a value to last_name, you can't just declare the name and the type of the variable, you need to assign a default value to it like that val last_name: String = ""

• Val cannot be reassigned:

And for this error because you set last_name as a value by using val and that means that you can't change it anymore, but you are trying to change it here this.last_name = lname, so to be able to change last_name you need to set is a variable by using var, like that var last_name: String = ""

So your final code should look like this:

class Person constructor(val first_name: String){ init{ println("Welcome, ${first_name}") } var last_name: String = "" constructor(fname: String, lname: String): this(fname){ this.last_name = lname } fun fullNameGreeting(){ println("Welcome, ${first_name} ${last_name}") } } fun main() { val kotlin = "🙂" println(kotlin) val adam: Person = Person("Adam", "Kim") } 

If you want to create an instance of Person with only first_name or both first_name and last_name, you can use this approach:

class Person constructor( val first_name: String, val last_name: String = "" ){ init{ println("Welcome, ${first_name}") } fun fullNameGreeting(){ println("Welcome, ${first_name} ${last_name}") } } 

This way you can either call Person("Your first name"), or Person("Your first name", "Your last name")