C++ In a Nutshell

Name

strtok function — Tokenizes a string

Synopsis

char* strtok(char* str, const char* delimset)

The strtok function splits str into separate tokens, separated by one or more characters from delimset. The contents of str are modified when each token is found.

To parse a string str, you must call strtok multiple times. The first time, pass str as the first parameter to strtok; for the second and subsequent calls, pass a null pointer. Because strtok saves str, only one series of strtok calls can be active at a time. Each call to strtok can use a different delimset.

The strtok function skips over initial delimiters, searching str for the first character that is not in delimset. If it reaches the end of the string without finding any token characters, it returns a null pointer. Otherwise, it saves a pointer to the first non-delimiter character as the start of the token. It then searches for the next delimiter character, which ends the token. It changes the delimiter character to a null character and returns a pointer to the start of the token. When strtok is called with a null pointer as the first parameter, it starts searching for the next token at the point where the previous search ended.

See Also

strcspn function, strpbrk function, strspn function, wcstok in <cwchar>