Scala函数获取下一个字母表的字母

Question

寻找要做的事情:

Given input: "s"
Expected output: "t"

Answer 1

def nextLetter(x:String) = (x(0) + 1).toChar.toString

Answer 2

scala> def f(s: String) = (s.head + 1).toChar.toString
f: (s: String)java.lang.String

scala> f("s")
res10: java.lang.String = t