[linuxiran] [OT] C programming, variable size array

[Aryan Ameri]

Hi There:

A while ago I was asked this question from a fellow friend of mine:

"Write a program, which promts the uset to enter some numbers. The user 
should terminate the sequence of numbers by entering EOF character. The 
program should put numbers entered by the user in to a 1D array".

Which seems pretty simple in first glance, but has one problem. When 
initializing the array, I don't know it's size (and I don't want to ask 
the user to enter it's size). The first soloution that came to my mind 
was to initialize the array to a very big number. However this is not 
elegant programming, and is a waste of memory. My second soloution was, 
to initialize the array inside the loop, so that it enlarges it's size 
continously each time the user inputs a number. I wrote the following 
code:

#include <stdio.h>

main()
{
int tmp, cnt = 0;
static int arr[cnt];
printf( "Enter Number\n");
scanf( "%d", &tmp);
while ( (tmp = getchar() ) != EOF ) {
        arr[cnt] = tmp;
        cnt += 1;
        static int arr[cnt];
        printf( "Enter Number\n");
        scanf( "%d", &tmp);
}

return 0;
}

This sounded logical to me. But the compiler (gcc 3.2) gives me a syntax 
error saying that 'storage size of 'arr' isn't constant'. Well, I don't 
want it to be constant!

I was wondering if any of you could help me solve this question. This is 
not yet-another-student-asking-for-help-to-do-homework. This is a 
problem for me, which has made me busy for a couple of days, and 
googling and greping /usr/include and other basic methods didn't reveal 
anything to me.

PS: Now that I am on the subject, can anyone point me to a active C 
mailing list? one that I can ask these kind of question from, as they 
come up? preferrably with a tendency towards Unix/Linux. (mailing lists 
please, not newsgroups).


Cheers
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Aryan Ameri