You're welcome
Type: Posts; User: copeg
You're welcome
The API is worth studying for all classes that you use. See String (Java Platform SE 6) and the substring method.
Write it out slowly on paper - loop through the string one character at a...
What did you try? Presuming you want a dash after the third and fifth number - did you try a loop? Have you tried breaking the input string into substrings?
Append of what? A string? What is ja? I don't understand the rules you describe. I recommend breaking what you need into these rules, its easier for us and a computer to understand.