Bugging ... Compile Time Error

I dont know whats terribly going wrong with this, well I know there's some memory allocation with this but I tried hard to fix it and when it gets fixed it doesn't shows up the desired value, this is the code that shows the compile-time error:

Code:

---

#include <stdio.h>
#include <string.h>

#define $WORD_LIST(X) "resource/" X

typedef struct char_type
{
        char** ptr;
}ccarray;

int ccarray_create(ccarray *c)
{
        c = (ccarray*)malloc(sizeof(ccarray*));
       
        c->ptr = (char**) malloc(sizeof(char**) * 1024);
        return 0;
}

int ccarray_insert(ccarray *c, char* str, int pos)
{
        c->ptr[pos] = str;
        printf("%d %s\n", pos, c->ptr[pos]);
}

int ccarray_destroy(ccarray *c)
{
        free( c->ptr );
        free( c );
        return 0;
}

int ccarray_read_file(ccarray* c, char* filename)
{
        FILE * fptr;
        char* line;
        int i;
       
        fptr = fopen(filename, "r");
        line = (char*) malloc(sizeof(char)*100);
        i = 0;
       
        while( fscanf(fptr,"%s",line) != EOF )
        {
                ccarray_insert(c, line, i);
                i++;
        }
        free(line);
        fclose(fptr);
}

int ccarray_print(ccarray* c)
{
        int i = 0;
        while ( c->ptr[i] != NULL )
        {
                printf("Line: %s\n", c->ptr[i] );
                i++;
        }
}

int main()
{
        ccarray * c;
        ccarray_create(c);
        ccarray_read_file(c, $WORD_LIST("sample.txt"));
        ccarray_print(c);
        ccarray_destroy(c);
        return 0;
}

---

... and this thing runs fine but doesn't shows any result:

Code:

---

#include <stdio.h>
#include <string.h>

#define $WORD_LIST(X) "resource/" X

typedef struct char_type
{
        char** ptr;
}ccarray;

int ccarray_create(ccarray **c)
{
        (*c) = (ccarray*)malloc(sizeof(ccarray));
        (*c) = (ccarray*)malloc(sizeof(ccarray));
        (*c)->ptr = (char**) malloc(sizeof(char**) * 1024);
        return 0;
}

int ccarray_insert(ccarray **c, char* str, int pos)
{
        (*c)->ptr[pos] = str;
        //printf("%s ", (*c)->ptr[pos] );
}

int ccarray_destroy(ccarray **c)
{
        free( (*c)->ptr );
        free( c );
        return 0;
}

int ccarray_read_file(ccarray** c, char* filename)
{
        FILE * fptr;
        char* line;
        int i;
       
        fptr = fopen(filename, "r");
        line = (char*) malloc(sizeof(char)*100);
        i = 0;
       
        while( fscanf(fptr,"%s",line) != EOF )
        {
                ccarray_insert(c, line, i);
                i++;
        }
        free(line);
        fclose(fptr);
}

int ccarray_print(ccarray** c)
{
        int i = 0;
        while ( (*c)->ptr[i] != NULL )
        {
                printf("Line: %s\n", (*c)->ptr[i] );
                i++;
        }
}

int main()
{
        ccarray * c;
        ccarray_create(&c);
        ccarray_read_file(&c, $WORD_LIST("sample.txt"));
        ccarray_print(&c);
        ccarray_destroy(&c);
        return 0;
}

---

what about posting the compilation arror as well?

in your first code ccarray_create will not update the pointer...
why not to return the allocated pointer? it will be easier

ok changed:

Code:

---

#include <stdio.h>
#include <string.h>

#define WORD_LIST(X) "resource/" X

typedef struct char_type
{
        char** ptr;
}ccarray;

ccarray* ccarray_create()
{
        ccarray* c = (ccarray*)malloc(sizeof(ccarray));
        c->ptr = (char**) malloc(sizeof(char**) * 1024);
        return c;
}

int ccarray_insert(ccarray *c, char* str, int pos)
{
        c->ptr[pos] = str;
        //printf("%s ", (*c)->ptr[pos] );
}

int ccarray_destroy(ccarray *c)
{
        free( c->ptr );
        free( c );
        return 0;
}

int ccarray_read_file(ccarray* c, char* filename)
{
        FILE * fptr;
        char* line;
        int i;
       
        fptr = fopen(filename, "r");
        line = (char*) malloc(sizeof(char)*100);
        i = 0;
       
        while( fscanf(fptr,"%s",line) != EOF )
        {
                ccarray_insert(c, line, i);
                i++;
        }
        free(line);
        fclose(fptr);
}

int ccarray_print(ccarray* c)
{
        int i = 0;
        while ( c->ptr[i] != NULL )
        {
                printf("Line: %s\n", c->ptr[i] );
                i++;
        }
}

int main()
{
        ccarray * c = ccarray_create(c);
        ccarray_read_file(c, WORD_LIST("sample.txt"));
        ccarray_print(c);
        ccarray_destroy(c);
        return 0;
}

---

The program ends up with displaying nothing. (The second one)

1. don't cast malloc in C
2. your insert function stores pointer to the external string
after you call insert - you delete the external string, so you get the dangling pointer that points to the memory you not own anymore
When you come to print it - results are unpredictable...
3. your scanf does not check buffer limits - better use fgets

Quote:

---

Originally Posted by vart

2. your insert function stores pointer to the external string
after you call insert - you delete the external string, so you get the dangling pointer that points to the memory you not own anymore
When you come to print it - results are unpredictable...

---

Yes, this is the only thing that I am concerned right now, No I do not delete it. See:

Code:

---

int ccarray_insert(ccarray *c, char* str, int pos)
{
        c->ptr[pos] = str;
        printf("%s ", c->ptr[pos] );
}


int ccarray_read_file(ccarray* c, char* filename)
{
....
........
        while( fscanf(fptr,"%s",line) != EOF )
        {
                ccarray_insert(c, line, i);
                i++;
        }
....
.............
}

---

The source file sample.txt contains:

Code:

---

EDIT
BLAH
WHATEVER

---

and, what I get in output of this program is :

Code:

---

Line:
Line:
Line:

---

It is getting the number of lines for a strange reason but not the lines themselves.

free(line); - here you release your pointer

all ptr[pos] now point to the address of line that is freed

Code:

---

c->ptr = (char**) malloc(sizeof(char**) * 1024);

---

and i guess this is not the right way of allocating the 2D array.

ssharish2005