fn pow10(exp: u32) -> u32 {
    var result: u32 = 1
    var i: u32 = 0
    while i < exp {
        result = result * 10
        i = i + 1
    }
    return result
}

fn digitCount(n0: u32) -> u32 {
    var n: u32 = n0
    var count: u32 = 0
    while n > 0 {
        count = count + 1
        n = n / 10
    }
    return count
}

fn cyclops(n: u32) -> Bool {
    let count: u32 = digitCount(n)
    if count % 2 == 0 {
        return false
    }
    let mid: u32 = count / 2
    if n / pow10(mid) % 10 != 0 {
        return false
    }
    var value: u32 = n
    var pos: u32 = 0
    while pos < count {
        let digit: u32 = value % 10
        if pos != mid && digit == 0 {
            return false
        }
        value = value / 10
        pos = pos + 1
    }
    return true
}

pub fn main(world: World) -> Void raises {
    if cyclops(105) && !cyclops(100) {
        check world.out.write("cyclops ok\n")
    }
}