1 int match(char *s1, char *s2) {

     2   while( *s1 != '\0' && *s2 != '\0' && *s1 == *s2 ){

     3     s1++; s2++;

     4   }

     5   return( *s1 - *s2 );

     6 }

     7 

     8 void welcome() { printf("Welcome to the Machine!\n"); exit(0); }

     9 void goodbye() { printf("Invalid identity, exiting!\n"); exit(1); }

    10 

    11 main(){

    12   char name[8];

    13   char pw[8]; 

    14 

    15   printf("login: "); 

    16   get_line(name);

    17   printf("password: "); 

    18   get_line(pw);

    19 

    20   if(match(name, pw) == 0)

    21     welcome();

    22   else

    23     goodbye();

    24 }