Longest line in C

thinkgeek · 08-23-2005, 09:32 AM

I want to enter the arbitrary line as long as possible from termiinal and then print the entered line when EOF is encountered. This has to be done without using system storage allocation functions such as malloc or realloc.

thinkgeek

itsme86 · 08-23-2005, 09:34 AM

There's no way to dynamically grow your buffer without using malloc(), etc. and you can't know how big to make the buffer beforehand. Why can't you use malloc()? Probably because it's homework.

thinkgeek · 08-23-2005, 10:18 AM

I just wanted to know/try whether is it possible without malloc/realloc.
Is it possible that you don't store at all and you first input 'entire string'
and then print entire string. (No storage could be required..)

thinkgeek

rstewart · 08-23-2005, 10:45 AM

Quote:

I just wanted to know/try whether is it possible without malloc/realloc.
Is it possible that you don't store at all and you first input 'entire string'
and then print entire string. (No storage could be required..)

If you input anything, you need to store it someplace in RAM. That is why you need to malloc/realloc the memory. In answer to your question, no it is not possible to input anything without preallocating a memory buffer to hold it. Storage in this case is RAM.

jim mcnamara · 08-23-2005, 12:06 PM

I think this may be what he means, but the 'storage' is pre-allocated:
[code]
int main(int argc, char *argv[])
{
printf("%s\n",argv[1]);
return 0;
}

usage: myprogram cmcmcmskfirurhjdj.....
displays the junk you typed.

So your C compiler should be able to take in as part of the command line 4096 characters - the POSIX1 standard for the number of chars that C exec functions can take as the total length of *argp + *envp.

In practice this number is larger.