我讀蘋果文檔的時候我就落到了這片語法:需要說明的雙標記函數聲明
struct Point {
var x = 0.0, y = 0.0
mutating func moveBy(x deltaX: Double, y deltaY: Double) {
x += deltaX
y += deltaY
}
}
var somePoint = Point(x: 1.0, y: 1.0)
somePoint.moveBy(x: 2.0, y: 3.0)
print("The point is now at (\(somePoint.x), \(somePoint.y))")
// Prints "The point is now at (3.0, 4.0)"
有人能解釋爲什麼moveBy(x deltaX: Double, y deltaY: Double)
對參數的雙標籤?