//(1) 自定义一个＊运算符，左边是String类型， 右侧为Int类型
func * (left: String,right: Int) -> String {
    
    var result = ""
    
    for i in 0..<right {
        result += "\(i)" + left
    }
    
    return result
}

let a = "Hello " * 3
println(a) //0Hello 1Hello 2Hello

//(2) 覆盖已知的运算符
func * (left: Int,right: Int) -> Int {
    return 0
}

let b = 10 * 10
println(b) //0

//(3) 自定义一个单项事运算符 ＋＋
postfix func ++ (left: Double) -> String {
    return  "\(left)" + "++"
}
println(0.0++) //0.0++

//(4) 复合运算符重载
func += (inout left: String,right: Int) {
    left = left + "\(right)"
}

var str = "aaaa"
str += 10
println(str) //aaaa10

//(5) 完全自定义符号 “<^|^>”  ［postfix］后置 ［prefix］前置 ［infix］二项演算
infix operator <^|^> {}
func <^|^> (left: Any,right:Any) -> String {
    return "