Complex.swift

struct Complex<T: FloatLiteralConvertible> {
    var real: T
    var imaginary: T
}

func +(lhs: Complex<Double>, rhs: Complex<Double>) -> Complex<Double> {
    return Complex<Double>(real: lhs.real + rhs.real, imaginary: lhs.imaginary + rhs.imaginary)
}

func -(lhs: Complex<Double>, rhs: Complex<Double>) -> Complex<Double> {
    return Complex<Double>(real: lhs.real - rhs.real, imaginary: lhs.imaginary - rhs.imaginary)
}

func *(lhs: Complex<Double>, rhs: Complex<Double>) -> Complex<Double> {
    return Complex<Double>(
        real: lhs.real * rhs.real - lhs.imaginary * rhs.imaginary,
        imaginary: lhs.imaginary * rhs.real + lhs.real * rhs.imaginary
    )
}

func /(lhs: Complex<Double>, rhs: Complex<Double>) -> Complex<Double> {
    let temp = rhs.real * rhs.real + rhs.imaginary * rhs.imaginary
    return Complex<Double>(
        real: (lhs.real * rhs.real + lhs.imaginary * rhs.imaginary) / temp,
        imaginary: (lhs.imaginary * rhs.real - lhs.real * rhs.imaginary) / temp
    )
}