c - Why is strtok changing its input like this?

Question

Ok, so I understand that strtok modifies its input argument, but in this case, it's collapsing down the input string into only the first token. Why is this happening, and what can I do to fix it? (Please note, I'm not talking about the variable "temp", which should be the first token, but rather the variable "input", which after one call to strtok becomes "this")

#include <string.h>
#include <stdlib.h>
#include <stdio.h>

int main(int argc, char* argv[]) {
   char input[]="this is a test of the tokenizor seven";
   char * temp;
   temp=strtok(input," ");
   printf("input: %s
", input); //input is now just "this"
}

Answer 1

When strtok() finds a token, it changes the character immediately after the token into a , and then returns a pointer to the token. The next time you call it with a NULL argument, it starts looking after the separators that terminated the first token -- i.e., after the , and possibly further along.

Now, the original pointer to the beginning of the string still points to the beginning of the string, but the first token is now -terminated -- i.e., printf() thinks the end of the token is the end of the string. The rest of the data is still there, but that stops printf() from showing it. If you used a for-loop to walk over the original input string up to the original number of characters, you'd find the data is all still there.