You have a string made up of 0, 1, and B (let's say, N B's) and you want to replace all the B's with 0's or 1's to make all the different (let's call them) Binary Strings, right?
First, understand the Problem without worrying about the Solution. Let's look at having N B's (let's say the B's are called "Bits"), so you have an N-Bit String and you want to replace each Bit with 0 or 1 to make all possible N-Bit (let's call them) Binary Numbers.
Do you know how to do that? Do you know how to generate all N-Bit Binary Numbers in some "natural" order? Then all you have to do is the following:
- For every N-bit Binary Number,
- Generate a String where all the B's are replaced by the Bits of the N-Bit Binary number.
I'll leave the Implementation of this simple scheme up to you. It will be a useful exercise in counting, logic, etc. You might find some functions on the Boolean Palette that fit nicely with this scheme. I suspect that you can "do it all" with a single For Loop, but you'll learn the most out of this exercise if you work it out on your own without much more help from the Forum (copying out a completed solution won't teach you as much as doing it yourself).
Bob Schor
