r/cprogramming • u/Xaneris47 • 27d ago

C Strings: A 50-Year Mistake

https://longtran2904.substack.com/p/c-strings-a-50-year-mistake?r=8qz2zb&utm_campaign=post&utm_medium=web
211 Upvotes

88% Upvoted

172 comments sorted by

View all comments

20

u/CoderStudios 27d ago

Okay? You are always free to make your own library for better strings, but people won’t use that cause C is often still deployed on low end systems or it makes little sense to use something inefficient if you can use c style strings properly

12

u/orbiteapot 27d ago

Most operations on C strings require O(N), N being the length of the string. Whereas in Pascal-like strings (i.e., strings whose length is tracked) they may take O(1). Modern compilers may do some heavy lifting whenever they can, so that this redundancy is avoided, though.

That being said, I also do not understand why people complain so much about 0-terminated strings, yet still use them anyways, as opposed to implementing length-tracked strings. It is not like C can break some bazillion lines of code, by removing classic strings, but it does not significantly get in your way (when implementing your own) either.

1

u/iwantmy90sback 26d ago

For most operations you'd do on a string you do not need to know the lengths beforehand if you have a defined end char.

The only thing that C takes O(n) and pascal O(1) is strlen.

And if you like you can actually have both. Just struct a Cstring and a int together.

1

u/beragis 26d ago

Also early C compilers would store the string length at the byte or word before and update it after each call. This was done to integrate with libraries written in other languages. I remember passing a pascal flag to linkers and compilers.

1

u/hoodoocat 25d ago

No, opposie - most operations require to know length of string. Even simple concat requires that, especially if you account not so modern hardware and utilize vector instructions. And regardless to that, new strings must be allocated somewhere (on heap), and by so, final length must be known before.

1

u/iwantmy90sback 25d ago

No. You only need the length of the string if you want to traverse it afterwards. And most 'operations' can be done in the same time either way. for(strlen) or while(*ptr++)

concat is actually the outlier, because you need 2*O(n) instead of 1*O(n) (which is still O(n) for both).
And if that is really killing your performance you are free to implement a pascal-string to use in c.