strtok It is C library string function Syntax include char strtok char str1 const char str2 Description The strtok function returns a pointer to the next token in str1 where str2 contains the delimiters that determine the token strtok returns NULL if no token is found In order to convert a string to tokens the first call to strtok should have str1 point to the string to be tokenized All calls after this should have str1 be NULL