How to make classes in Kotlin?

A Kotlin class is defined in its simplest form by declaring its members in the class declaration itself.

class Book(var bookname:String,var subject:String,var price:Int) {

    override fun toString(): String

    {

       return "Book Name=$bookname, Subject = $subject, Price=$price"

    }

}

fun main(args: Array<String>)

{

    var b=Book("Basic C","C",100)

    println(b.toString())

}

The portion in bold is the toString method and gives a string representation of the class.

Class with init block

class Book(var bookname:String,var subject:String,var price:Int) {

    init {

        println("book name stored $bookname")

    }

    init {

        println("book subject stored $subject")

    }

    init {

        println("book price stored $price")

    }

    val discountedprice:Double =price.toDouble()*90.0/100.0

    override fun toString(): String

    {

       return "Book Name=$bookname, Subject = $subject, Price=$price, Discounted Price=$discountedprice"

    }

}

fun main(args: Array<String>)

{

    var b=Book("Basic C","C",100)

    println(b.toString())

}

Class with static method

class Book(var bookname:String,var subject:String,var price:Int) {

    init {

        println("book name stored $bookname")

    }

    init {

        println("book subject stored $subject")

    }

    init {

        println("book price stored $price")

    }

    val discountedprice:Double =price.toDouble()*90.0/100.0

    companion object {

        val classdetails = "This is a book class"

        fun details():String { return classdetails }

    }

    override fun toString(): String

    {

       return "Book Name=$bookname, Subject = $subject, Price=$price, Discounted Price=$discountedprice, Detail = $classdetails"

    }

}

fun main(args: Array<String>)

{

    var b=Book("Basic C","C",100)

    println(b.toString())

    println(Book.details())

}