Task:

 Generate a string with   N   opening brackets   [   and with   N   closing brackets   ],   in some arbitrary order. 
 Determine whether the generated string is balanced; that is, whether it consists entirely of pairs of opening/closing brackets (in that order), none of which mis-nest.


Examples

   (empty)      OK
   []           OK   
   [][]         OK   
   [[][]]       OK 
   ][         NOT OK
   ][][       NOT OK
   []][[]     NOT OK



function CheckBrackets(string s) as bool
'=======================================
  sys co, le=len s
  byte b at strptr s
  indexbase 0
  for i=0 to <le
    select b(i)
    case "[" : co++
    case "]" : co--
    end select
    if co<0 then return 0
  next
  if co=0 then return 1
end function
 
 
'TEST
'====
 
print CheckBrackets ""    '1
print CheckBrackets "["   '0
print CheckBrackets "]"   '0
print CheckBrackets "[]"  '1
print CheckBrackets "[[]" '0
print CheckBrackets "[]]" '0
print CheckBrackets "[][]"'1
print CheckBrackets "]["  '0
 