Simple function problem

Hello.

I have um simple program that just count how many args are introduced by user.

Example: insert 20 30 should say 3 args. The problem is i can count the args correctly but one of my variavles changes and i don't want.

Code:

#include<stdio.h>
#include<stdlib.h>
#include <readline/readline.h>
#include <readline/history.h>
#include <string.h>

int num_args(char *op)
{
int number=0;
char *temp;
temp = strtok (op," ");
  while (temp != NULL)
  {
number++;
/*    printf ("%s\n",pch);*/
    temp = strtok (NULL, " ");
  }
  return number;
}

int main ()
{
char *r;
int a;
r=readline("LETRAS: ");
a=num_args(r);
printf("Number of ARGS: %d and comand:%s\n",a,r);
}

as you can see i want to keep r as it was after user insert the comand, but when i passed to function changes.
Help me please....

Tks
HIT

If you don't want to change the string, strtok is not for you. Or alternatively you can create a copy of the command string and call strtok on that.