Summer 2015 part2 Day3 quiz2, about reentrancy, should add some mechanism to prevent out-of-boundary access...?

quiz2_tjc_version.c

#include <stdio.h>
#include <string.h>
//wrapper function of strtok
/*strIn, can be NULL, then the result output will use lastState to manipulate */

char* strtok_tj_r(char* restrict strIn, const char* restrict tokens, char** restrict lastState)
{
  char* result;
  if(strIn!=NULL){
    result = strtok(strIn,tokens);//the string has been modified by strok with token char replace by eof
   *lastState = result+1+strlen(result);//save the next position in the state string, +1 for the token(now eof)
  }
  else{
    if((*lastState)==NULL){
      return NULL;
    }
    result = strtok(*lastState, tokens);
    *lastState = result+1+strlen(result);
    if(strlen(*lastState)==0){
      *lastState=NULL;
    }
  }
   return result;
}
int main(void)
{
char test[80]={0};//need to initialize these with 0... otherwise get char '?' behind eof ... cause unexpected behavior
char blah[80]={0};
     char *sep = "\\/:;=-";
     char *word, *phrase, *brkt, *brkb;

     strcpy(test, "This;is.a:test:of=the/string\\tokenizer-function.");

     for (word = strtok_tj_r(test, sep, &brkt);
          word;
          word = strtok_tj_r(NULL, sep, &brkt))
     {
         strcpy(blah, "blah:blat:blab:blag");

         for (phrase = strtok_tj_r(blah, sep, &brkb);
              phrase;
              phrase = strtok_tj_r(NULL, sep, &brkb))
         {
             printf("So far we're at %s:%s, brkt:%s, brkb:%s\n", word, phrase, brkt, brkb);
         }
     }
     return 0;
}

the output:
So far we're at This:blah, brkt:is.a:test:of=the/string\tokenizer-function., brkb:blat:blab:blag
So far we're at This:blat, brkt:is.a:test:of=the/string\tokenizer-function., brkb:blab:blag
So far we're at This:blab, brkt:is.a:test:of=the/string\tokenizer-function., brkb:blag
So far we're at This:blag, brkt:is.a:test:of=the/string\tokenizer-function., brkb:(null)
So far we're at is.a:blah, brkt:test:of=the/string\tokenizer-function., brkb:blat:blab:blag
So far we're at is.a:blat, brkt:test:of=the/string\tokenizer-function., brkb:blab:blag
So far we're at is.a:blab, brkt:test:of=the/string\tokenizer-function., brkb:blag
So far we're at is.a:blag, brkt:test:of=the/string\tokenizer-function., brkb:(null)
So far we're at test:blah, brkt:of=the/string\tokenizer-function., brkb:blat:blab:blag
So far we're at test:blat, brkt:of=the/string\tokenizer-function., brkb:blab:blag
So far we're at test:blab, brkt:of=the/string\tokenizer-function., brkb:blag
So far we're at test:blag, brkt:of=the/string\tokenizer-function., brkb:(null)
So far we're at of:blah, brkt:the/string\tokenizer-function., brkb:blat:blab:blag
So far we're at of:blat, brkt:the/string\tokenizer-function., brkb:blab:blag
So far we're at of:blab, brkt:the/string\tokenizer-function., brkb:blag
So far we're at of:blag, brkt:the/string\tokenizer-function., brkb:(null)
So far we're at the:blah, brkt:string\tokenizer-function., brkb:blat:blab:blag
So far we're at the:blat, brkt:string\tokenizer-function., brkb:blab:blag
So far we're at the:blab, brkt:string\tokenizer-function., brkb:blag
So far we're at the:blag, brkt:string\tokenizer-function., brkb:(null)
So far we're at string:blah, brkt:tokenizer-function., brkb:blat:blab:blag
So far we're at string:blat, brkt:tokenizer-function., brkb:blab:blag
So far we're at string:blab, brkt:tokenizer-function., brkb:blag
So far we're at string:blag, brkt:tokenizer-function., brkb:(null)
So far we're at tokenizer:blah, brkt:function., brkb:blat:blab:blag
So far we're at tokenizer:blat, brkt:function., brkb:blab:blag
So far we're at tokenizer:blab, brkt:function., brkb:blag
So far we're at tokenizer:blag, brkt:function., brkb:(null)
So far we're at function.:blah, brkt:(null), brkb:blat:blab:blag
So far we're at function.:blat, brkt:(null), brkb:blab:blag
So far we're at function.:blab, brkt:(null), brkb:blag
So far we're at function.:blag, brkt:(null), brkb:(null)