Tips? Sure.
You could search through the passed string for the occurance of the desired character. Perhaps using 'strchr()' or by cycling through the array and comparing each element.
Code:
for (i = 0; i < strlen(PassedInString); i ++)
if (PassedInString[i] == ThisCharacter) // do something about it
Then simply get the characters that occured before the matched element and return them. Repeat your search for the required character n times or until you reach the end of the string.
P.S. This: 'gettok(this is a string,1,32)' will generate any number of errors. You mean this: 'gettok("this is a string",1,32)'