将评论读入动态大小的数组

Question

So i have a series of comments in my markup file:

# comment1
# comment2

I want to read these into an array to be added to a comment array in my struct. I do not know the amount of comment lines in advance

I declare the comment array in my struct as follows:

char *comments; //comment array

Then I am starting to read the comments in but what i've got wasn't working:

int c;
//check for comments
c = getc(fd);
while(c == '#') {
    while(getc(fd) != '\n') ;
    c = getc(fd);
}
ungetc(c, fd);
//end comments?

Am I even close?

Thanks

Answer 1

First

char *comments; //comment array

Is one comment not an array of comments.

You need to use realloc, to create an array of strings

char**comments = NULL;
int count = 10; // initial size
comments  = realloc(comments, count);

when you get > count

count*=2;
comments = realloc(comments, count);// classic doubling strategy

to put a string into the array (assuming comment is a char* with one comment in it

   comments[i] = strdup(comment);

Answer 2

You can use fgets() form <stdio> to read one line at at time.

int num_comments = 0;
char comment_tmp[82];
char comment_arr[150][82];
while(comment_tmp[0] != '#' && !feof(file_pointer)){
    fgets(comment_tmp, 82, file_pointer);
    strcpy(comment_arr[num_comments], comment_tmp);
    num_comments++;
}

This has the limitation of only being able to store 150 comments. This can be overcome by 1) setting a higher number there, 2) using dynamic memory allocation (think malloc/free), or 3) organizing your comments into a more flexible data structure like a linked list.

Answer 3

When you see that line is comment store the value of comment in comment variable just go to next line and do this loop again. So the code :

char c = getc(fd);
while(c == '#') {
    while(getc(fd) != '\n') /* remove ; */ {
    *comment = getc(fd);
    ++comment;
    }
}

or use fscanf which is easier :

fscanf(fd,"#%s\n",comment); /* fd is the file */

Note that comment here is a string not an array of string.

For array of string it would be :

#define COMMENT_LEN 256

char comment [COMMENT_LEN ][100];
int i = 0;
while(!feof(fd) || i < 100) {
     fscanf(fd,"#%s\n",comment[i]);
     getch(); /* To just skip the new line char */
     ++i;
}