Consider the following C program:

void abc(char *s)
{
   if(s[0]=='\0') return;
   abc(s+1);
   abc(s+1);
   printf("%c",s[0]);
}
main()
{ 
   abc("123");
}

(a) What will be the output of the program?
(b) If abc(s) is called with a null-terminated string s of length n characters (not counting the null ('\0') character), how many characters will be printed by abc(s)?