program SteelCost;
{ program computing cost of steel needed for counted lots of ballbearings
          and roller bearing lots with flag-controlled loop.

R. Rosebrugh
October 5, 1993}

const Price = 0.52;    {price per cc of steel - the units used below}

var   More, BType : Char; {input - loop control and bearing type}
      Radius, Length : Real;    {input - radii in cm }
      LotSize, Lotcount : Integer;   {input - numbers required}
      Counter : Integer;
      Flag: Boolean;        {loop control}
      Volume, Cost  : Real; {output - volumes and cost}

procedure Ball;
{process ball-bearing lots}
begin
    WriteLn ('Type the radius (decimal number) in centimetres');
    WriteLn ('lot size (whole number) and lot count for ball bearings');
    ReadLn (Radius,Lotsize,Lotcount);
    Counter := 1;
    Volume := 0.;
    while Counter < LotCount do
     begin
       Volume := 4/3*Pi*Sqr(Radius)*Radius*Lotsize + Volume;
       Counter := Counter + 1
     end{While Counter}
end{Ball};

procedure Roller;
{process roller-bearing lots}
begin
    WriteLn ('Type the radius and length (decimal numbers) in centimetres');
    WriteLn ('and lot size (whole number) for roller bearings');
    ReadLn (Radius,Length,Lotsize);
    Volume := Pi*Sqr(Radius)*Length*Lotsize;
end{Roller};

begin{main program}
    Cost := 0.; {initialize accumulating variable}
    Flag := False; {initialize flag to false}
    while not(Flag) do
      begin
           WriteLn ('What type of lot? Type ''B'' for ball, ''R'' for roller');
           Readln (BType);
           if Btype='B'then
              Ball
           else if Btype='R' then
             Roller
           else
             WriteLn ('Input error, ignore program output');
           Cost := Volume * Price + Cost;
           Writeln ('Another lot?');
           ReadLn (More);
           if More<>'Y' then {or equivalently Flag := (More <> 'Y')  }
                Flag := True
      end;{while More}
     WriteLn ('The total cost is  $', Cost:5:2);
end.