Thread: some help needed->size of 2D array

Hi, I would definitely use some help on this:
I've got a list of words in a .txt file. 1 word for 1 line. First I count the \n's to get the number of words and then I put the words to the array I defined by doing(size is number of words):

Code:

char chDizi[size][22];
do{
        fscanf(ptDosya01,"%s",&chDizi[j]);
        j++;
        }while(j<size);

now as you see, the size of the second dimension of the array is 22 which is a limit for me and that is my problem. I have words longer than 22 char.'s, so I need to define the size as 30 or so. And if I put a number bigger then 22(23 for example) , I get an error message from the system (not the compiler) saying my program needs to be shut, when I try to run it.

So, I'll be very thankful if you help me find why this happens and what should i do. Thanks very much.

> char chDizi[size][22];
Well this isn't legal C either - you're relying on compiler extensions.

The first step would be

Code:

char **lines = malloc ( size * sizeof *lines );

Then your loop would be

Code:

do{
    char buff[BUFSIZ];
    fscanf(ptDosya01,"%s",buff);
    lines[j] = malloc( strlen(buff) + 1 );
    strcpy( lines[j], buff );
    j++;
}while(j<size);

>I get an error message from the system (not the compiler) saying my program needs to be shut
Either:
(1) You're using an old compiler (like Turbo C), or
(2) you've got a bug in your program.
If it's (1), you'll either have to declare the array global, or using dynamic memory allocation. Something similar to this:

Code:

char *chDizi[size];
int j = 0;
do {
   fscanf(ptDosya01, "%s", word);
   chDizi[j] = malloc(length_of_word + 1);
   strcpy(chDizi[j], word);
   j++;
} while(j<size);

If it's (2), fix the bug.

Originally Posted by creon

Thnx for your answers. When I use either of the ways, I get the same error message " invalid conversion from `void*' to `char*' " for the line with the command malloc. Do you know why thi is?

Because you're compiling your C program as C++.

Originally Posted by creon

well, i guess i've solved my problem. i needed to add (char*) just before malloc. Thank you very much for helping me out.

That's not the best solution. You're still compiling your C program as C++. You'll likely end up running into other unexpected problems if you continue down this path.

The best fix would be to make sure you're actually compiling your program as a C program. Different IDEs handle this differently. Maybe it's in project options, maybe you just need to make sure your source code filename ends in .c instead of .cpp.

Originally Posted by esbo

Have you tried?

[code]
char chDizi[size][40];
do{
fscanf(ptDosya01,"%s",&chDizi[j]);
j++;
}while(j<size);
[/code

It's obvious he's just running out of stack space. What exactly is your solution supposed to solve? Dynamic memory allocation, as Salem already pointed out, is the correct solution.

Experience. Go read up on how memory is laid out and how the stack works. He could definitely run out of stack space very quickly if, like swoopy mentioned, he's using an older 16-bit compiler.

<sarcasm>From the way you don't take advice from anyone, I assumed you had a higher level of knowledge and experience.</sarcasm>

It's called typecasting. Basically you're telling the compiler to treat whatever it is you're typecasting as the type you're casting it as. In your case, you were telling the compiler that the return type of malloc() was char * which is not necessary in C.

http://faq.cprogramming.com/cgi-bin/...&id=1043284351