Jednoduchá kalkulačka

{ KALKULACKA.PAS                                                    }
{ Jednoducha kalkulacka.                                            }
{                                                                   }
{ Datum:26.11.2011                             http://www.trsek.com }
 
program kalkulacka;
 uses crt;
 var a,b : real;
 n : char;
 begin
 clrscr;
 repeat
 writeln('Zadaj cislo');
 readln(a);
 writeln('Zadaj operator (+,-,*,/), 0 = end');
 n:= readkey;
 if ord(n)<>48 then
 begin
 writeln(n);
 writeln('Zadaj cislo');
 readln(b);
 case n of
 '+': a:=a+b;
 '-': a:=a-b;
 '*': a:=a*b;
 '/': a:=a/b;
 end;
 writeln(' ');
 writeln('= ',a:3:2);
 writeln(' ');
 end
 else break;
 until ord(n)=48;
 end.