realloc not working for 2-D pointer array

Question

In the following code, I ask the user to give me some strings. I make a 2-D pointer char array, so that I read the input with pointer string which points to the start of a string of length 50. My problem is that I keep crashing after the input of the first string.. and I assume that my problem has to do with the realloc. I am not used to it.. can you please help to figure out what is happening?? I tried to debug with netbeans, but didn't manage to see anything interesting, since it doesn't give feedback for the new addresses made from realloc!!

Here is the code:

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

int main()
{
    char *str,**string,buffer[50],temp[2];
    int i,j,q,size,counter;
    size=10;
    string=(char**) calloc(size,sizeof(char*));
    for (i=0; i<size; i++) string[i]=(char*) malloc(50*sizeof(char));
    printf("\nGimme strings, terminate input with x");
    i=0;
    gets(string[i]);
    temp[0]=120;//x
    temp[1]='\0';
    size=0;
    while(strcmp(string[i],temp)!=0)
    {
        string=realloc(string,size*sizeof(char**));
        i++;
        gets(string[i]);
        size++;
        counter++;
    }
return 0;
}

I want to make the table of pointers bigger with this realloc.

Answer 1

    string=realloc(string,size*sizeof(char**));
    i++;
    gets(string[i]);
    size++;

After you call realloc to enlarge string, the new portion contains no valid pointers. So when you call gets, you're passing it a pointer you failed to initialize.

Also, that size=0; is totally broken.