(* control.3.pasc *)
(* complex control structures, perform the
 * 1. if-then-else structure
 * 2. loop structure
 * 3. nesting control structure  
 *
 *)

program Control3 is

constant 
	nl = '\n';

var
	a, b, i, j: integer;
begin
	write('Give me two intergers a and b -> ');
	read(a, b);
	write(nl);

	if a = 0
	then if b = 0
	     then write('a=0 and b=0 \n')
	     else if b>0
	            then write('a=0 and b>0\n') 
	            else write('a=0 and b<0\n') 
	          endif
	     endif
	elsif a>0
	then if b = 0
	     then write('a>0 and b=0\n')
	     else if b>0
	            then write('a>0 and b>0\n') 
	            else write('a>0 and b<0\n') 
	          endif
	     endif
	elsif b = 0
	then write('a<0 and b=0\n')
	else if b>0
	       then write('a<0 and b>0\n') 
	       else write('a<0 and b<0\n'); 
	     endif
	endif;
	     
	write(nl);

	for i := 1 to 3 loop
	  for j := 1 to 3 loop
	    if i >= j then write(i,' ',j);   write(nl);  endif;
	  endloop;
	endloop;
 
	write(nl);

	j := 1;
	while j <= 3 loop
	  i := j;
	  repeat
	    write(i,' ',j);
	    write(nl);
	    i := i+1;
	  until i > 3;
	  j := j+1;
	endloop;

	write(nl);

	i := 5;
	while i >= 10 loop
	    write(nl);
	    write('I should not be here....');
	    write(nl);
	endloop;

	i := 1;
	repeat
	    i := 5*i;
	    write('I shoule be here just once for ', i, nl);
	until i > 3;
end.


(*
 * INPUT:
 *	Give me two intergers a and b -> -4 -5
 * OUTPUT
 *	a<0 and b<0
 *
 *	1	1
 *	2	1
 *	2	2
 *	3	1
 *	3	2
 *	3	3
 *
 *	1	1
 *	2	1
 *	3	1
 *	2	2
 *	3	2
 *	3	3
 *	
 *	I should be here just once for 5
 *)