how to round only one corner in swift code example

Example 1: add top corner radius swift

extension UIView {
   func roundCorners(corners: UIRectCorner, radius: CGFloat) {
        let path = UIBezierPath(roundedRect: bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
        let mask = CAShapeLayer()
        mask.path = path.cgPath
        layer.mask = mask
    }
}

Example 2: round down swift

let number = 0.1
// Use ceil to remove the fractional part and round up.
let result = ceil(number)


let number1 = 1.1
// Use floor to remove the fractional part and round down.
let floor1 = floor(number1)