Rumus Kalkulator Empat Proses ( + - x :)

Ini rumus kalkulator sederhana :D

var
b1, b2,i, operasi :integer;
hasil : real;

begin
write ('bilangan 1 = ');
read (b1);
write ('bilangan 2 = ');
read (b2);
write ('operasi = 1(+) 2(-) 3(/) 4(*) 5(^)');
read (operasi);
hasil:=1;

if (operasi = 1) then
hasil := b1+b2
else if (operasi = 2) then
hasil := b1-b2
else if (operasi = 3) then
hasil := b1/b2
else if (operasi = 4) then
hasil := b1*b2
else if (operasi = 5) then
for i:= 1 to b2 do
begin
hasil := hasil*b1;
end;
write ('hasilnya = ', hasil :7:2);
end.