FizzBuzz - I don't know what is wrong with this code , please help

Well, just looking at your code and not the challenge, there are a couple of issues:

On line 10, you are missing an "if".

And then on 14, the syntax is incorrect and the function needs to return a string, so that should be:

return "(n)"

That will get rid of the errors, but the function is flawed in that it is always stepping through the same numbers 1 through 100 no matter what value you pass into it.

So, your code fixed should look like this:

func fizzBuzz(n: Int) -> String {
  // Enter your code between the two comment markers
  for n in 1...100{
    if (n % 3 == 0) && (n % 5 == 0) {
      return "FizzBuzz"
    }
    else if (n % 3 == 0) {
      return "Fizz"
    }
    else if (n % 5 == 0) {
      return "Buzz"
    }
    else {
      return "\(n)"
    }
  }
  // End code
  return "\(n)"
}

But the function won't do anything except return 1 every time it's called, so I'd drop the for loop and the last else statement, and go with something like this:

func fizzBuzz(n: Int) -> String {
  // Enter your code between the two comment markers
  if (n % 3 == 0) && (n % 5 == 0) {
    return "FizzBuzz"
  } else if (n % 3 == 0) {
    return "Fizz"
  } else if (n % 5 == 0) {
    return "Buzz"
  }
  // End code
  return "\(n)"
}

That function actually works and can be called like:

let result = fizzBuzz(n: 15)

and it actually functions.

Hope this helps.