Thread: How to use strtok?

strtok is used to parse strings. Like in your phone number example you can use the parenthesis as a marker that seperates the data you actually want. You call strtok and pass it the string you want to deal with and the seperator you want to use. You can call it multiple times to get the next field. In which case you would use a NULL as the string, and you can change the delimiter each time as needed.


Actual doc:
The strtok subroutine breaks the string pointed to by the String1 parameter into
a sequence of tokens, each of which is delimited by a byte from the string
pointed to by the String2 parameter. The first call in the sequence takes the
String1 parameter as its first argument and is followed by calls that take a
null pointer as their first argument. The separator string pointed to by the
String2 parameter may be different from call to call.

--Bonkey

Sounds like homework...

Originally posted by fuh
Sounds like homework...

I think this is a good way to ask for help, he is not asking for the whole homework, he wants to know to use strtok().

Well...
To tokenize a string you have to make sequential calls to strtok(), untill you get NULL in the string returned by strtok()...
char *strtok( char *string1, const char *s2);
where string1 is the string to want to tokenize.
String2 is are the character that the tokinizing is based on.

I'll show you how does it work by an example:

Code:

char []string="bla bla bla";
char *tokenPtr;

tokenPtr = strtok( string, " ");

while ( tokenPtr != NULL )
{
     cout << tokenPtr << '\n';
     tokenPtr = strtok( NULL, " ");
}

Bit late - I mean, the thread was over a year old before being bumped

and seeing as how no one seems to have mentioned it already, go to msdn.microsoft.com if you know the name of a function but want to know how to use it.

Been there, done that, for this exact function. Took one look at the docs, and looked for an alternate solution (and I never did find out how the function worked until today) Personally, I find that the docs are often overly technically-precisely worded, making the meaning of the whole thing obscure and hard to grasp.

**EDIT**
DOH, even that post was a couple years old...

Originally Posted by talz13

so if you use a delimiter string such as "()-", will it token the string based on each individual character from that string, or will it look for that string to tokenize?

like if i wanted to token '-', '|', '/', and ' ', i would just make the delimiter string "-|/ "?

Try it and see.