Print right-angled-triangle or isosceles-triangle

Triangle.swift

// mode: 0 是 直角三角形, 1 是 等腰三角形
// size: 邊長

func printer(mode: Int, size: Int) {
    
  // Print a right angled triangle
  func rightAngledTriangle() {
    var i = 1
    while i <= size {
      var string = ""
      for _ in 0..<i { string += "*" }
      print(string + "\n")
      i += 1
    }
  }
    
  // Print a isosceles triangle
  func isoscelesTriangle() {
    var i = size - 1
    while i >= 0 {
      var string = ""
      for _ in 0..<i { string += " " }
      let count = (size - i - 1) * 2 + 1
      for _ in 0..<count { string += "*" }
      print(string + "\n")
      i -= 1
    }
  }
    
   (mode == 0) ? rightAngledTriangle() : isoscelesTriangle()
}