type zesp = float * float

let ( +++ ) (z1: zesp) (z2: zesp) =
    let (a, b) = z1
    let (c, d) = z2
    in ((a+c), (b+d))

let ( --- ) (z1: zesp) (z2: zesp) =
    let (a, b) = z1
    let (c, d) = z2
    in ((a - c), (b - d))

let ( *** ) (z1: zesp) (z2: zesp) =
    let (a, b) = z1
    let (c, d) = z2
    in (a * c - b * d, a * d + b * c)

let ( /../ ) (z1: zesp) (z2: zesp) =
    let (a, b) = z1
    let (c, d) = z2
    in ((a * c + b * d) / (c ** 2.0 + d ** 2.0),
        (b * c - a * d) / (c ** 2.0 + d ** 2.0))

[<EntryPoint>]
let main argv =
    let z1 = (5.0, 3.0)
    let z2 = (3.0, 5.0)
    printfn "%A" <| z1 +++ z2
    printfn "%A" <| z1 --- z2
    printfn "%A" <| z1 *** z2
    printfn "%A" <| z1 /../ z2
    0 // return an integer exit code