Smart way to generate permutation and combination of String

Question

String database[] = {\'a\', \'b\', \'c\'};

I would like to generate the following strings sequence, based on given database.

Answer 1

This smells like counting in binary:

• 001
• 010
• 011
• 100
• 101
• ...

My first instinct would be to use a binary counter as a "bitmap" of characters to generate those the possible values. However, there are several wonderful answer to related questions here that suggest using recursion. See

• How do I make this combinations/permutations method recursive?
• Find out all combinations and permutations - Java
• java string permutations and combinations lookup
• http://www.programmerinterview.com/index.php/recursion/permutations-of-a-string/