Версия для печати темы

program postf;
uses
    PostUnit, Crt;
var

   s:string;
   l:longint;

begin
     ClrScr;
     Writeln('Vvedite postficsalnoe viragenie (primer: "10 15 + 2 * 10 / 5 +" otvet: 10; pisat bez kavichek) ');
     s:='';
     ReadLn(s);
     Stroka(s,l);
     Writeln(l);
     Readkey;
end.

Unit PostUnit;

interface

Type
    Ukaz=^ stek;
    Stek = record
                 num1:longint;
                 next:Ukaz;
end;

Var
   top,P:Ukaz;

procedure AddStek(znak:longint);
procedure DelStek;
procedure obrabotka(dey:integer);
procedure Stroka(str:string; result:longint);

implementation

{procedure AddStek(znak:longint);}
procedure AddStek;
begin
     New(P);
     P^.num1:=znak;
     P^.Next:=top;
     top:=P;
end;

procedure DelStek;
begin
     P:=top;
     top:=top^.Next;
     Dispose(P);
end;

{procedure obrabotka(dey:integer);}
procedure obrabotka;
var
   N:integer;
begin
     if dey=1 then   { + }
     begin
          P:=top;
          N:=P^.num1;
          P:=P^.Next;
          N:=N+P^.num1;
     end
     else
     if dey=2 then   { - }
     begin
          P:=top;
          N:=P^.num1;
          P:=P^.Next;
          N:=N-P^.num1;
     end
     else
     if dey=3 then  { * }
     begin
          P:=top;
          N:=P^.num1;
          P:=P^.Next;
          N:=N*P^.num1;
     end
     else
     if dey=4 then  { / }
     begin
          P:=top;
          N:=P^.num1;
          P:=P^.Next;
          N:=round(N/P^.num1);
     end;
     DelStek;
    { DelStek;}
     AddStek(N);
end;


{procedure Stroka(str:string; result:longint);}
procedure Stroka;
var
   code,i:integer;
   m:longint;
   zn:string;
begin
     While str<>' ' do
     begin
          i:=i+1;
          if str[i]=' ' then
          begin
               zn:=copy(str,0,i);
               str:=copy(str,i,length(str)-i+1);
               i:=0;
               m:=0;
               if zn='+' then obrabotka(1) else
               if zn='-' then obrabotka(2) else
               if zn='*' then obrabotka(3) else
               if zn='/' then obrabotka(4) else
               begin
                    val(zn,m,code);
                    AddStek(m);
               end;
          end;
     end;
     P:=top;
     Result:=P^.num1;
end;

end.