Kotlin:
複素数の扱い方

data class Complex(val real: Double, val imaginary: Double) {
    operator fun plus(other: Complex) = Complex(real + other.real, imaginary + other.imaginary)
    operator fun minus(other: Complex) = Complex(real - other.real, imaginary - other.imaginary)
    operator fun times(other: Complex) = Complex(
        real * other.real - imaginary * other.imaginary,
        real * other.imaginary + imaginary * other.real
    )
    
    override fun toString(): String = "($real + ${imaginary}i)"
}

fun main() {
    val a = Complex(1.0, 2.0)
    val b = Complex(3.0, 4.0)
    
    println("a + b = ${a + b}")  // 出力： a + b = (4.0 + 6.0i)
    println("a - b = ${a - b}")  // 出力： a - b = (-2.0 - 2.0i)
    println("a * b = ${a * b}")  // 出力： a * b = (-5.0 + 10.0i)
}