Swift 闭包

闭包的本质就是函数，没有函数的func关键字和函数名

代码如下 

var numArray:[Int] = [];for _ in 0 ... 100 {    numArray.append(random() % 1000)}numArray.sort({(a:Int , b:Int) -> Bool in    return a > b})

// 简化闭包let newArray = numArray.sort({a, b in a > b})let newArray2 = numArray.sort({$0 < $1})