Very strange behavior possibly involving strtok

I've encountered a very strange issue that may or may not be caused by strtok.

Let me first just say that I can work around this by writing the program a different way, but at this point I'm just puzzled as to why this is going on.

Code:

---

int main()
{
        char* buffer[2] = {0, 0};
        long size50, size10;

        readFile("50000words.txt", buffer[0], size50);
        readFile("10000words.txt", buffer[1], size10);

        char **a;
       
        //entryList and lookupList contain pointers to locations in buffer[0]/[1] respectively.
        char *entryList[numEntries],
                *lookupList[numLookups];
        int entryVals[numEntries],
                lookupVals[numLookups];

        const char delim[] = ", \n\r";
       
        int i = 0;
        entryList[0] = strtok(buffer[0], delim);
       
        cout << entryList[0] << endl;        //Tetraheism
       
        while(entryList[i] != NULL && i < numEntries)
        {
                entryVals[i] = atoi(strtok(NULL, delim));
                entryList[++i] = strtok(NULL, delim);
        }
       
        cout << entryList[0] << endl;        //Tetraheism
        cout << entryList[1] << endl;        //Chrisoms
       
       
        lookupList[0] = strtok(buffer[1], delim);
       
        cout << entryList[0] << endl;        //Tetraheism
        cout << entryList[1] << endl;        //Chrisoms
       
        i = 0;
        while(lookupList[i] != NULL && i < numLookups)
        {
                lookupList[++i] = strtok(NULL, delim);
        }
       
        cout << entryList[0] << endl;        //chwartzlot  <---- WHAT? this string is towards the end of the buffer.
        cout << entryList[1] << endl;        //Chrisoms

---

So, I'm a bit puzzled as to exactly what could have happened here. Even more so because only pointed-to value of the first element of entryList has changed.

entryList[0] points to a location in buffer[0]. Casting entryList[0] to void* in the cout statement shows that the address pointed to changes. Can anyone explain why?

You walk off the end of the lookupList array, by accessing lookupList[numLookups] which doesn't exist. (Since you're doing pre-increment, you get an off-by-one error even though the while loop "looks" right.)

Ah jeez, and here I was thinking it was some sort of ridiculous error caused by strtok.

I've spent too much time spent in the safety of Java. I guess I expected some sort of exception to be thrown by going out of bounds.

Thanks, fixed up the loops and it works fine now :).