Thread: pointer-copying

probably with writing one more row it accessing to memory where it shouldnt be
because output gives this

Code:

2.
2.1
2.2
2.3
2.4
Value 4
Value 5
Value 9
2.5
2.6
   He    Be    Ce
    4     5     9
2.7
   He    Be    Ce
    4     5     9
2.8
   He    Be    Ce
    4     5     9
2.1
   He    Be    Ce
    4     5     9
2.2
2.3
   He    Be    Ce
    4     5     9
2.4
Value 2
Value 7
Value 3
   He    Be    Ce
    4     5     9
2.5
2.6
   He    Be    Ce
    4     5     9
   He    Be    Ce
    2     7     3
2.7
   He    Be    Ce
    2     7     3
2.8
   He    Be    Ce
    2     7     3
2.1
   He    Be    Ce
    2     7     3
2.2
2.3
   He    Be    Ce
    2     7     3
2.4
Value 2
Value 5
Value 1
   He ♥├ľŕ‼¨   ě►/

And my changes in code :

Code:

row *create_row(int values[], char tab_name[]) {
    printf("2.1\n");
    if (find_tab(tab_name)->first_row != NULL) {
        print_row(find_tab(tab_name),find_tab(tab_name)->first_row);
    }
    tab *tab_temp = find_tab(tab_name);

    printf("2.2\n");
    row *actual = malloc(sizeof(row));
    item *first_item;

    printf("2.3\n");
    item *last_added = NULL;
    int i;
    if (tab_temp->first_row != NULL) print_row(tab_temp,tab_temp->first_row);

    printf("2.4\n");

    for (i = 0; i < tab_temp->columns_count; i++) {
        item *iter = malloc(sizeof(item));
        iter->value = values[i];
        iter->next = NULL;
        if (last_added) {
            last_added->next = iter;
        }
        else {
            first_item = iter;
        }
        last_added = iter;
        printf("Value %d\n",iter->value);
    }

    if (tab_temp->first_row != NULL) print_row(tab_temp,tab_temp->first_row);

    printf("2.5\n");
    actual->first_item = first_item;
    actual->next = NULL;

    printf("2.6\n");
    if (tab_temp->first_row != NULL) print_row(tab_temp,tab_temp->first_row);
    if (tab_temp->first_row == NULL) {
        tab_temp->first_row = actual;
    }
    else {
        actual->next = tab_temp->first_row;
        tab_temp->first_row = actual;
    }
    if (tab_temp->first_row != NULL) print_row(tab_temp,tab_temp->first_row);

    printf("2.7\n");
    print_row(tab_temp,tab_temp->first_row);

    printf("2.8\n");
    return actual;
}

Are the "He Be Ce" coming from a hard-coded string, or are those stored in memory somewhere? If so, we may be unmasking a bug from those strings being stored somewhere you didn't have access to.

Code:

typedef struct Column {
	char name[10];
	struct Column *next;
	//struct Column *previous;
} column;

Yeah, so if you did that linked list anything like you did the linked-list here .... You may want go back and check that.

I hope im not overweighting this structure with adding new rows (i mean from memory side)

Originally Posted by Holymanus

I hope im not overweighting this structure with adding new rows (i mean from memory side)

That's not really possible. Each of these structs is, what, eight bytes? 24 bytes a row is not a huge memory deal. I'm still betting on "messed up linked list of column headings".

No i meaned that OS allocated for this tab struct place and im giving there more and more but there is only pointer so it is not what getting bigger

Im trying put there only things which belong there. Now it is all right. One more time thank you for help