Why won't this compile? ``` val numberOfDoorsIndex = args.indexOf("--numberOfDoors") val num...

# getting-started

[benleggiero]

Why won't this compile?

val numberOfDoorsIndex = args.indexOf("--numberOfDoors")
    val numberOfDoors: Int
    if (numberOfDoorsIndex > 0 && args.size > numberOfDoorsIndex) {
        val userSetNumberOfDoorsString = args[numberOfDoorsIndex]
        try {
            numberOfDoors = max(3, abs(userSetNumberOfDoorsString.toInt()))
        }
        catch (ex: NumberFormatException) {
            numberOfDoors = 3 // error here
        }
    }

error:

Error:(22, 13) Kotlin: Val cannot be reassigned

Obviously it isn't going to be; if the NumberFormatException is thrown, it was never assigned in the first place!

[kartikpatodi]

Firstly making a variable val means yoh cannot modify the value and it needs to be initialized although you can use lateInit
Try using var

[russhwolf]

I guess the compiler can't tell if the assignment in the try block would happen before or after the exception is thrown. In any event, maybe try using if and try as expressions, ie

val numberOfDoors = if (numberOfDoorsIndex > 0 && args.size > numberOfDoorsIndex) {
    val userSetNumberOfDoorsString = args[numberOfDoorsIndex]
    try {
        max(3, abs(userSetNumberOfDoorsString.toInt()))
    }
    catch (ex: NumberFormatException) {            
        3
    }
}

[kartikpatodi]

well https://youtrack.jetbrains.com/issue/KT-13802#comment=27-1604906

[russhwolf]

Oh yeah that's still a very similar issue. Guess it probably is best to just go with var

[kartikpatodi]

maybe or could implement the newer approach

[marstran]

Try-catch is an expression though, so you could just do numberOfDoors = try { ... } catch (ex: NumberFormatException) { ... }