which are formed accordng to the E B NF below. A period terminates the input. 

Expression = Term { ( "+" I "-" ) Term} . Term = Factor { "*,, Factor }. Factor = Identifier "(" Expression ")" . Identifier = Letter. 

program PostFix (Input,Outpu' ); { Program 11.5 - Convert an infix expression to Polish I ostfix form. label 13 { premature end f file }; var Ch: Char; procedure Find; begin if Eof(Input) then goto 13; repeat Read (Input, Ch); until (Ch <> ' ') or Eo: (Input) end { Find }; procedure Expression; var Op: Char; procedure Term; procedure Factor; begin if Ch = ' (' then begin Find; ExpJession; {Ch else Write (Output, Ch); Find end { Factor }; begin { Term } Factor; while Ch , *, do , )' } end begin Find; Facto]; Write (Output, '*') end end { Term }; begin { Expression Term; while (Ch = '+') or (Ch = '-') do begin Op := Chi Find; TE rm; Write (Output, Op) end end { Expression }; 

