Introduction to Annotation Classes

import java.math.BigDecimal
import java.math.MathContext
class Money(
    val amount: BigDecimal,
    val currency: String,
) {
    @Throws(IllegalArgumentException::class)
    operator fun plus(other: Money): Money {
        require(currency == other.currency)
        return Money(amount + other.amount, currency)
    }
    companion object {
        @JvmField
        val MATH = MathContext(2)
        @JvmStatic
        fun eur(amount: Double) =
            Money(amount.toBigDecimal(MATH), "EUR")
        @JvmStatic
        fun usd(amount: Double) =
            Money(amount.toBigDecimal(MATH), "USD")
        @JvmStatic
        fun pln(amount: Double) =
            Money(amount.toBigDecimal(MATH), "PLN")
    }
}
fun main() {
    // Create instances of Money using the provided companion object functions
    val money1 = Money.eur(100.50)
    val money2 = Money.eur(75.25)
    // Perform addition of money amounts with the plus operator
    val result = money1 + money2
    // Print the result
    println("Money 1: ${money1.amount} ${money1.currency}")
    println("Money 2: ${money2.amount} ${money2.currency}")
    println("Sum: ${result.amount} ${result.currency}")
}