[Swift 4 Update]add parentheses

Single argument function types require parentheses

Author: iWeslie

Binary Tree/BinaryTree.swift

@@ -29,23 +29,23 @@ extension BinaryTree: CustomStringConvertible {
 }
 
 extension BinaryTree {
- public func traverseInOrder(process: T -> Void) {
+ public func traverseInOrder(process: (T) -> Void) {
  if case let .node(left, value, right) = self {
  left.traverseInOrder(process: process)
  process(value)
  right.traverseInOrder(process: process)
  }
  }
 
- public func traversePreOrder(process: T -> Void) {
+ public func traversePreOrder(process: (T) -> Void) {
  if case let .node(left, value, right) = self {
  process(value)
  left.traversePreOrder(process: process)
  right.traversePreOrder(process: process)
  }
  }
 
- public func traversePostOrder(process: T -> Void) {
+ public func traversePostOrder(process: (T) -> Void) {
  if case let .node(left, value, right) = self {
  left.traversePostOrder(process: process)
  right.traversePostOrder(process: process)