When two numbers have the same "weight", let us class them as if they were strings and not numbers: ... 180 is before 90 since, having the same "weight" (9), it comes before as a string.

That basically means comparison by character codes. First non-equal comparison wins. '1' comes before '2', so 1anything also comes before 2anything.

As it turns out, string comparison in basically every language already works this way.

If we're going to engage in pedantry, the correct use would be "Hello, Name. How are you?" :)

I saw a pattern pretty much immediately, but i also started with more moving parts. :P Probably took 15-30 minutes farting around with concatenation before i saw a less clunky way.

Just published a NASM translation.

• Maskify.Maskify(""); // should return ""

Throwing an exception is not "change all but four chars.."

And null is not "".

In nearly all cases where you're passing null instead of a string, it is an error. IMO, it should cause an exception, unless you have a well-defined behavior for that case, as otherwise you're allowing bugs to propagate.

And let the caller, who I assume have accee to user interface and such, to handle possible errors caused by a null string

Except you're making it much more difficult to handle those errors at the source.

Most of the other solutions will fail if cc == null as well...and frankly, that's the right thing to do, unless the problem specifies a behavior for that case.

C++ random tests sometimes have p > n. What's worse, they expect a value that doesn't even make sense in that case.

Workaround: just keep submitting til tests succeed.