Can some one tell me the algorithm of Token based extractio of straight lines?

And where can I find the related topics?
Thanks a lot!

something like this:

char *tokenPtr
char string[ ]

tokenPtr = strtok(string, " ");
while(tokenPtr != NULL)
tokenPtr = strtok(NULL, " ");

-strtok() will begin to parse the string on the first call to it. the delimiter character is the second argument, which in this case is a space. after the first call, u set up a while loop as above. now if u want to be able to store these tokens, then that will require some additional code, good luck!
-dont forget to #include<string.h> !

Thank you!
However, what I want is just a algorithms of image processing.
Some kind of image recognization.

Thank u all the same!