Coding Kombinasi (Delphi)

procedure TForm4.Button27Click(Sender: TObject);
var n, p,q, i,x,k,r: integer;
c:real;
begin
n:= strtoint (edit2.Text);
p:=1;
for i:=1 to n do
begin
p:= p*i;
end;

k:= strtoint (edit3.Text);
q:=1;
for i:=1 to k do
begin
q:=q*i;
end;

x:=n-k;
r:=1;
for i:=1 to x do
begin
r:=r*i;
end;

c:= p /(q*r) ;
edit4.Text:= floattostr (c);

end;