Ambiguous reference to member when using ceil or round

Question

I am just trying to use the `ceil` or `round` functions in Swift but am getting a compile time error: Ambiguous reference to member 'ceil'. I have already imported the `Foundation` and `UIKit` modules. I have tried to compile it with and without the `import` statements but no luck. Does anyone one have any idea what I am doing wrong? my code is as follow; ``` import UIKit @IBDesignable class LineGraphView: GraphView { override func setMaxYAxis() { self.maxYAxis = ceil(yAxisValue.maxElement()) } } ```

Accepted Answer

This problem occurs for something that might seem strange at first, but it's easily resolved.

Put simply, you might think calling `ceil()` rounds a floating-point number up to its nearest integer, but actually it doesn't return an integer at all: if you give it a `Float` it returns a `Float`, and if you give it a `Double` it returns a `Double`.

So, this code works because `c` ends up being a `Double`:

```
let a = 0.5
let c = ceil(a)
```

…whereas this code causes your exact issue because it tries to force a `Double` into an `Int` without a typecast:

```
let a = 0.5
let c: Int = ceil(a)
```

The solution is to convert the return value of `ceil()` to be an integer, like this:

```
let a = 0.5
let c = Int(ceil(a))
```

The same is true of the `round()` function, so you'd need the same solution.

Ambiguous reference to member when using ceil or round

Solution

Problem