Thread: Pointer to pointer, dynamic memory, help pls

Hello, I'm trying to write a program which makes a dynamic array of all different words, so if a word is already entered before, it doesn't add the word.

This is my code:

Code:

/* AUTH: Kevin Strijbos
   DATE: 07/02/2012
   DESC: excercise 14.5.1 */


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


#define MAX_WORDS 10


int check_appearance (char* *words, char *toCheck, int index);


int main (void)
{
	char* *pntr;
	char buffer[21];
	int counter, index;


	pntr = NULL; // initialize pntr
	index = 0; // keeps track of the amount of words in pntr


	for (counter = 0; counter < MAX_WORDS ;counter++)
	{
		printf("Enter a word: ");
		fgets(buffer, sizeof(buffer), stdin);


		/* delete newline */
		if (buffer[strlen(buffer)-1] == '\n')
			buffer[strlen(buffer)-1] = '\0';


		if (check_appearance(pntr, buffer, index) == 0)
		{
			pntr = (char* *)(realloc(pntr, sizeof(char *) * (index+1)));
			*(pntr+index) = (char *)(malloc(sizeof(buffer)+1)); // +1 for the \0
			strcpy((*(pntr)+index), &buffer[0]);
			index++;
		}
	}


	/* print list */
	for (counter = 0; counter < index ;counter++)
	{
		printf("WORD %d: %s\n", *(*(pntr+counter)));
		free(*(pntr)+counter);
	}
	
	free(pntr);


	return 0;
}


/* checks if a word is already entered */
int check_appearance (char* *words, char *toCheck, int index)
{
	int counter, found;


	found = 0;


	for (counter = 0; found == 0 && counter <= index ;counter++) // index: how many words there are in the list - 1 (counter is passed)
	{
		if (strcmp(*(words + counter), toCheck) == 0)
			found = 1;
	}


	return found;
}

Now, the program doesn't work. I think the problem has something to do with the strcmp and strcpy.

It compiles and runs, but when I enter a word I get an error.
Anyone got an idea?

Didn't know I can use the index notation with pointers, thanks for the tip, I'll try it that way!

Damn, still don't find it. Been stuck on this for hours now.

Well, I'll explain my theory:
When it finds a word that isn't in the list yet, it adds one char pointer to the memory block where pntr is pointing to.
Then, I let that char pointer point to a memory block with the size of the entered word.

How I compare the list and the word:
I check for every word in the list if it's matched with the word...

There are so many problems in your code...

1. there are no words in your list... and you try to compare it with input word? from where the compiler will generate a list?????
2. <b> char buffer[21]; /</b> this one should be memset to 0 or NULL <advice>.
3. words is pointing to no where that is why it is getting crashed..

There are so many problems in your code...

1. there are no words in your list... and you try to compare it with input word? from where the compiler will generate a list?????
2. <b> char buffer[21]; /</b> this one should be memset to 0 or NULL <advice>.
3. words is pointing to no where that is why it is getting crashed..