strtok without string.h

#include <stdio.h>

 static char* _last = NULL;

 char *strtok( char* str, char token ) {
     char *ptr = NULL;
     if ( str ) {
        ptr = str;
        _last = str;
        while ( *_last && *_last != token ) _last++;
        if ( *_last ) *_last = 0;
        else _last = NULL;
     } else {
        if ( _last ) {
            *_last = token;
            _last++;
            ptr = _last;
            while ( *_last && *_last != token ) _last++;
            if ( *_last ) *_last = 0;
            else _last = NULL;
        }
     }

     return ptr;
 }

int main() {
    char x[] = "alma korte cseresznye a b c";
    char * y = strtok( x, ' ' );
    while( y ) {
        printf( "%s\n", y );
        y = strtok( NULL, ' ' );
    }
    return 0;
}