Swift error: 'missing return in function'?

Question

I am creating a tic tac toe game and I came upon this error that I don't really understand: "Missing return in a function expected to return '(location:String, pattern:String)'". It is drawing the error on this block of code that should return "algorResults", which should give a location and pattern (both Strings) as was initialized on the first line. What's going wrong? Please thoroughly explain suggestions, thanks! My code:

//Function that implements part of AI that sees where a good place to play is:

func rowcheck(value:Int)->(location:String, pattern:String)? {
    var goodFinds = ["011","101","110"]
    var findFuncs = [checktop, checkbottom, checkmidAcross, checkleft, checkmidDown, checkright, checkLRdiag, checkRLdiag]
    for algor in findFuncs {
        var algorResults = algor(value)
        if find(goodFinds,algorResults.pattern) {
            return algorResults
        }
    }
}

Not familiar with swift, but to hazard a guess, I think it is complaining that not all code paths return a value. What would happen if the 'find' method returns false? Your method does not return anything in that case! — link64
– link64, Commented Jul 11, 2014 at 3:11

shree.pat18 · Accepted Answer · 2014-07-11 03:11:41Z

9

Your code only returns a value if find(goodFinds,algorResults.pattern) is satisfied, but there is no return value otherwise.

What you can do is to specify a default return value and do something like this (pseudo-code only):

variable result = defaultvalue

if find(goodFinds,algorResults.pattern) {
        result = algorResults
    }

return result

I should mention that I am not familiar with Swift, but this logic would ensure that you always return something, so that your method fulfills the contract.

answered Jul 11, 2014 at 3:11

shree.pat18

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1 Comment

Mark Tomlin Over a year ago

Yep you're exactly correct! You can not have a function where there is ever a possibility of not returning a value, the SWIFT compiler will balk at any code that does not return in all circumstances.

Upworks · Accepted Answer · 2015-08-21 15:47:25Z

2

Since your return type is an optional, you could do this:

func rowcheck(value:Int)->(location:String, pattern:String)? {
  var goodFinds = ["011","101","110"]
  var findFuncs = [checktop, checkbottom, checkmidAcross, checkleft, checkmidDown, checkright, checkLRdiag, checkRLdiag]
  for algor in findFuncs {
    var algorResults = algor(value)
    if find(goodFinds,algorResults.pattern) {
        return algorResults
    }
  }
   return nil
}

answered Aug 21, 2015 at 15:47

Upworks

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Comments

valeriana · Accepted Answer · 2018-07-03 14:28:52Z

0

You could use a switch statement. Here is an example I have used:

  func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    let button = DropDownButton()
    switch button {
    case userButton:
        return userButton.dropView.dropDownOptions.count
    case categoryButton:
        return categoryButton.dropView.dropDownOptions.count
    default:
        return 0
    }

Thought it might help somebody, Happy coding

answered Jul 3, 2018 at 14:28

valeriana

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Comments

Robert · Accepted Answer · 2020-03-06 17:35:31Z

0

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    let button = DropDownButton()
    switch button {
    case userButton:
        return userButton.dropView.dropDownOptions.count
    case categoryButton:
        return categoryButton.dropView.dropDownOptions.count
    default:
        return 0
    }

edited Mar 6, 2020 at 17:35

Robert

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answered Mar 6, 2020 at 16:47

priyanshu patel

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1 Comment

Nicholas Tulach Over a year ago

Hey, it helps a lot if you use the code formatting in your replies. Just three back-ticks on a single line above and below.

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