So I'm following through with project 5 and have followed closely until the end of the first section of part 2. When I compile and run, I run into the error "attempt to insert row 0 into section 0, but there are only 0 rows in section 0 after the update". This error occurs only after I click Submit to enter my answer so that it can be inserted at row: 0, section: 0. I have double checked my code and can not find a difference between mine and the one Paul provides.

Here is the code for my submit function

func submit(_ answer: String) {
        let lowerAnswer = answer.lowercased()

        if isPossible(word: lowerAnswer) {
            if isOriginal(word: lowerAnswer) {
                if isReal(word: lowerAnswer) {
                    usedWords.insert(answer, at: 0)

                    let indexPath = IndexPath(row: 0, section: 0)

                    tableView.insertRows(at: [indexPath], with: .automatic) //the exact line that seems to be causing my crash

                }
            }
        }
    }

Here is the code for my promptForAnswer function as well, in case that is of use:

@objc func promptForAnswer() {
        let ac = UIAlertController(title: "Enter answer", message: nil, preferredStyle: .alert)
        ac.addTextField()

        let submitAction = UIAlertAction(title: "Submit", style: .default) { 
            [weak self, weak ac] action in 

            guard let answer = ac?.textFields?[0].text else { return }
            self?.submit(answer)
        }

        ac.addAction(submitAction)
        present(ac, animated: true)
    }

Okay that is confusing, but can you show your tableView load data?

Yeah super confusing, to me esspecially, I'm assuming this is what you need?

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Word", for: indexPath)
        cell.textLabel?.text = usedWords[indexPath.row]
        return cell
    }

To those who also may run into this problem, When adding

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return usedWords.count
    }

I accidently pressed tab to autofill when typing in "numberOf" and it autofilled to

   override func numberOfSections(in tableView: UITableView) -> Int {
        return usedWords.count
    }

and I hadn't noticed. This is what was causing the crash and removing this function fixed my code and is now running as it is supposed to. Thanks @roosterboy for suggesting I take a look at the numberOfRowsInSection portion of my code!