Breaking strings without using strtok()

Hey there~ Im looking for a way to break a string into substrings without the use of strtok()...I wrote my own function but i think there are some bugs in it but i just cant seem to find out the problem...Hope you all will help me out here...Thanks in advance for the help!!

Code:

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

int main()
{
  char string[50];
  char words[60][60];
  int wordNum = 0;
  int charNum;
  int length, i, j;

  fgets(string,sizeof(words),stdin);

  length = strlen(string);

  for(i = 0; i < length; i++)
  {
    charNum = 0;

    if(!isspace(string[i]))
    {
      words[wordNum][charNum] = string[i];
      charNum++;
    } 

    else
    {
      wordNum++;
    }
  }

  printf("\n\n");

  for(i = 0; i <= wordNum; i++)
  {
    for(j = 0; words[i][j] != '\0'; j++)
    {
	if(isalnum(words[i][j]))
        printf("%c",words[i][j]);
    }

    printf("\n\n");
  }

  return 1;
}

Code:

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

int main()
{
  char string[50];
  char words[60][60];
  int wordNum = 0;
  int charNum = 0;
  int length, i, j;

  fgets(string,sizeof(string),stdin);

  length = strlen(string);

  for(i = 0; i < length; i++)
  {

    if(!isspace(string[i]))
    {
      words[wordNum][charNum] = string[i];
      charNum++;
    }

    else
    {
      words[wordNum][charNum] = '\0';
      wordNum++;
      charNum = 0;
    }
  }

  printf("\n\n");

  for(i = 0; i < wordNum; i++)
  {
    for(j = 0; words[i][j] != '\0'; j++)
    {
	if(isalnum(words[i][j]))
        printf("%c",words[i][j]);
    }

    printf("\n\n");
  }

  return 0;
}

-.- And it took me so long to find out the problem...Thanks a lot for the help! It works just fine now!!