More problems with string manipulation and seg faults

[Acolyte]

Alright, here's what I'm working on now. It's supposed to go through an inputted list of words, pick out actual words and create a numbered list of them, then, where it finds a number in the list, go back in the list from that number, replace it with a word, augment the list accordingly and continue.

Anyways, here's what I have:

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
 
int main ()
{
    char line[100];
    char word[100];
    char tword[20];
 
    int k, index, nwords = 0, j;    
 
    gets(line);
 
    while(line[0] != '0')
    {
        if(isalpha(line[k]))     
        {
            j = 0;
            while (isalpha(line[k]))
            {
                tword[j] = line[k];
                j++;
                k++;
            }
            tword[j] = '\0';
            strcpy(word[nwords], tword);
            nwords++;
        }
        else if(isdigit(line[k]))
        {
            index = atoi(line[k]);
            k++;
            if(isdigit(line[k]))
            {
                index = index * 10  + atoi(line[k]);
                k++;
            }
            printf("%s", word[nwords - index]);
            strcpy(tword, word[nwords-index]);
            for(j  = index + 1; j < nwords; j++)
            {
                strcpy(word[j - 1], word[j]);
            }
            strcpy(word[nwords - 1], tword);
        }
        else
        {
            printf("%c", line[k]);
            k++;
        }
    gets(line);    
    }
    return 0;
}

The problem is that I get segmentation faults when executing. Anybody see what I'm missing?

[Banfa]

k is never initialised

[Acolyte]

Yeah, I noticed that right after I posted. However, I've changed that now, to no avail.

[horace1]

an obvious problem is line 28

            strcpy(word[nwords], tword);
 

word[] is an array of char, it should be an array of char* or char[], e.g.

    char word[100][20];