Difference: JaysJournal (38 vs. 39)

06/11/10

I also did a few benchmarks on a bunch of string vs char array functions, and I've developed the following guidelines for any future compatability issues or conversions:

• Converting a string to char array using std::string::c_str() or std::string::data() are negligibly fast, so don't worry about doing it!
• There's no difference as far as I can see between std::string::data() and std::string::c_str() in terms of speed.
• Converting a char array to string (using std::string(const char *) or std::string::operator=(const char *)) is very slow (O(n)), avoid as much as possible.
• Using strncpy with some pointer math and appending a NULL is much faster than string::substr (something like 4-5x faster).
• std::string::operator[] is a bit slower than char array's [] operators as well, probably because the string does bounds checking (not sure on this). Even doing std::string::c_str(), then using the [] operator is faster (though not by much)
• Also, be wary of the string's operator=(const char *) assignment, which sometimes masks a char array --> string conversion. Try being as explicit as possible when setting a string equal to a char array (by using the constructor), to avoid confusion

Finally, I think I might take Chris up on his offer for taking a break to study for my MCAT. I'll see how far I get on the weekend, but I might take Monday off for an extra study day. I guess we'll see after the weekend.

To do:

• Finish the conversion by getting stuff to compile! (I really hope saligner ends up being faster).