#include <string.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
        char tmp;
        char *b, *e;

        char* str = malloc(7);
        strcpy(str,"foobar");
        for (b=str,e=str+strlen(str)-1; b<e; b++,e--)
        {
                tmp = *b;
                *b =*e;
                *e = tmp;
        }
        printf("%s",str);
}