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)?

What is printed by the print statements in the program P1 assuming call by reference parameter passing?

Program P1()
{
     x=10;
     y=3;
     func1(y,x,x);
     print x;
     print y;
}
func1(x,y,z)
{
     y=y+4;
     z=x+y+z;
}

Consider the following program

Program P2
      var n:int;
      procedure W(var x:int)
      begin
          x=x+1;
          print x;
      end

      procedure D
      begin
          var n:int;
          n=3;
          W(n);
      end
begin     \\begin P2
      n = 10;
      D;
end

If the language has dynamic scooping and parameters are passed by reference, what will be printed by the program?

Consider the following problem $$X.$$ Given a Turing machine $$M$$ over the input alphabet $$\sum , $$ any state $$q$$ of $$M$$ And a word $$w\,\,\varepsilon \,\,\sum {^ * ,} $$ does the computation of $$M$$ on $$w$$ visit the state $$q''$$

Which of the following statements about $$X$$ is correct?