Need Ideas for C Functions

[guidj0s]

Hi guys. I'm gonna go straight to the point. I'm creating a set of functions which will hopefully be useful for C programmers. They're intended to focus on string manipulation. What do I need? Ideas.

If you can think of any task involving character arrays which is frequently performed and is also a bit annoying, then do let me know so I can include a proper function.

If anyone wants to talk to me directly, you can find me on hackerthread's irc channel or add me on msn: guidjos0x00 { at] gmail.com

Thanks in advance.

[IceDane]

Well, to be honest, there aren't many string functions that are left for you to implement that would be insanely useful. They made most of the standard ones available.

The fact that C uses character arrays makes it that much more difficult to deal with strings. You can't, for example, split strings up in a nice manner, without resorting to a dirty hack using static variables in your function like strtok does, or by risking a memory leak in returning an array of pointers, that might not get freed up properly.

Well, hmm, that might be an idea, though. You could create a version of strtok, and accompanying cleanup function, that returns an array of pointers, each of which point to a token. The catch would be to allocate memory for (sizeof(char*) * (no_tokens + 1)) so that you have space for a NULL pointer denoting ending.

[guidj0s]

Well there's an idea

Think I'm gonna code that.

Still, there are varied operations which might be useful and aren't yet implemented. The original C libraries include all the basic functions, I'm just adding up a few more specific ones

Thanks for the penny. If anyone else has more ideas, please speak up.

[mfukar]

Here's a few:

• a function that counts the number of occurences of substring sub in a range [start, end] within a string str.
• a function that encodes a string str in a specified encoding (some popular choices would be UTF-8, UTF-16, base64, hex, bz2..)
• an analogous decoding one
• a function to left/right justify a string in a string of specified length, using a specified filling character.
• a reverse strstr()
• strip() (leading & trailing whitespace as specified)
• a partitioning function which, given a string and a separator, returns the part before the separator, the separator itself, and the part after the separator.

...to go, please.

[guidj0s]

NICE. That's just what I needed.

I'm currently coding a function that will take a pointer to FILE as a parameter and return an array of strings, each containing a line of the file (the zeroth index being the first line of the file, and the last one, a NULL pointer). Might come in handy, who knows.

But thanks for the ideas, I do like them. I have a test tomorrow, and that means two more days of studying, but after that I'll get back to coding.

Thanks again. I had also asked for suggestions in other forums but with no success.

[mfukar]

You could take a look at higher level languages and check their string manipulation functions, that might give you some inspiration. I just wish I'd keep count of how many times I wished for a function like Python's replace...

[TheMuFFenMann]

Yeah no shit haha. After using some of pythons string functions i decided to do the same thing like a year ago and just write a C header with any string manipulation function i could think of...i think i had like 25 or so going but then the code just got to the point where the code got so convoluted from trying to achieve the ease of use as in python that i just said forget it, i have to go to work. but i do think that this is one area where C could really use some work. it'd make life so much easier

[tektonik]

i was looking at your countoccurrences() function and thought to myself that i could find it useful if it optionally returned the the address of each occurance. or took an argument and returned the adress of the specified occurrence. something to think about.

[Kheldar]

i was looking at your countoccurrences() function and thought to myself that i could find it useful if it optionally returned the the address of each occurance. or took an argument and returned the adress of the specified occurrence. something to think about.

strstr() already returns the address of a certain string within a string .

http://www.cplusplus.com/reference/clib ... ng/strstr/