Thread: reset strtok()

Originally Posted by laserlight

the solution is to copy the string, then call strtok with the copy.

What is wrong in my code?

Code:

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

int main(void)
{
    char *pos1, *pos2;
    char string[256];
    
    printf("Enter a string: ");
    fgets(string, 255, stdin);
    
    pos1 = string;
    char copy[strlen(string)+1];
    strcpy(copy, string);
    pos1 = strtok( string, " ,");    
    while (pos1) {
        pos2 = strtok( copy, " ,");
        while (pos2) {
printf("pos2 %s\n", pos2); //for debug
            if(!strcmp(pos1, pos2) && (string-pos1)<(copy-pos2))
                puts(pos2);
            pos2 = strtok( NULL, " ,");
        }
printf("pos1 %s\n", pos1); //for debug
    pos1 = strtok( NULL, " ,");
    }

    return 0;
}

Originally Posted by SashaN

What is wrong in my code?

Code:

pos1 = strtok( string, " ,");    
while (pos1) {
    pos2 = strtok( copy, " ,");

You can't use strtok one two different strings simultaneously. The moment you use strtok() on "copy", tokenizing "string" doesn't work any more. The reason is that strtok() saves internally the state of the current string processing, thus if you provide a new string, this information is overwritten.
If you really want to tokenize two strings you could use the non-standard strtok_r (e.g. supported by the GNU C Library) or strtok_s (new in C11).

Bye, Andreas