How to find out next character alphabetically?

Question

How we can find out the next character of the entered one. For example, if I entered the character \"b\" then how do I get the answer \"c\"?

Answer 1

How does ä sort? In German (I think) it should sort after a, but in Swedish it should come after å, which in turn is after z. This is not a trivial question, unless you restrict yourself to English.