Thread: need help with implementing realloc

Edit: you need to add a cast before malloc. array = (char *) malloc(sizeof(string));

Malloc returns a void pointer.

Originally Posted by Tool

Edit: you need to add a cast before malloc. array = (char *) malloc(sizeof(string));

Malloc returns a void pointer.

You should never cast the return of malloc, all it will do is hide the fact that you haven't included stdlib.h in your program

If string is defined as char * string; that means sizeof(string) will likely be 4 or whatever the size of a pointer to char is on your system.

You need to make string big enough to fit whatever data you're putting in, ie if string was:

Code:

char * string = "some words here and some words";

your malloc would then need to allocate enough memory to store 6 pointers each of varying sizes, or just find the largest word and allocate 6 (6 words) char arrays each of the maximum size little bit more difficult than you thought, eh?

So if we were to go with your earlier code, it would look something like this:

Code:

                char * temp = NULL;
                char ** array = NULL;
...
...
                array = malloc(word_count);	/* word_count should be number of pointers to char we need in array */
		temp = strtok(string," ");		
		array[0] = malloc(strlen(temp) + 1);	
                strcpy(array[0],temp);
		for(i=1; i<= word_count-1;i++)
		{
                        temp = strtrok(NULL," ");
			array[i] = malloc(strlen(temp) + 1);
                        strcpy(array[i],temp)
		}

something like that with lots more error checking, this is a total minimalist almost pseudo code, as you can see from the work thats being done (this without ANY error checking) this is very sloppy approach.

One other thing, it's usually not a good idea to call strtok on a string defined as char * string = "blah blah blah" because strtok modifies the string its called on.