////////   comparing strings     ///////
#include <iostream.h>

int strcmp(const char *r, const char *s)
{
        while (*r == *s)
        {       if (*r == '\0') return (0);
                r++; s++;
                }
        return(*r - *s);
        }

main()
{  char * a="abcd";
   char * b="abd";
   if (strcmp(a,b)  < 0) cout << "OK\n";
}