We could go like this.
function tform1.adv(a,b:real):real;
begin
adv:=a+b;
end;
The problem is the return is real, which is single value only. We want a and b as vector. Wait...
How we define vector in Delphi? I don't know. I used to treat a vector in Delphi as array. So I coded it like this
var a,b:array[0..1]of real;
So far I had no problem. Lately, I am going crazy with overuse functions in Delphi, and trying operating vectors using function too.
But if I write the code like this
function tform1.adv(a,b:array[0..1]of real):real;
begin
adv:=a[0]+b[0];
{a[1]+b[1]?}
end;
It will only return one value. So I improvised by modify it
like this
function tform1.adv(a,b:array[0..1]of real):array[0..1]ofreal;
begin
adv[0]:=a[0]+b[0];
adv[1]:=a[1]+b[1];
end;
But it won't compile. (it will give error message "identifier expected but ARRAY found"). So I try another approach
type
vector=array[0..1] of real;
function tform1.adv(a,b:vector):vector;
begin
adv[0]:=a[0]+b[0];
adv[1]:=a[1]+b[1];
end;
It works, :).
Here my last night tinkering with "vector" in Delphi, :)
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, Math;
type
vector=array[0..1] of real;
type
TForm1 = class(TForm)
procedure proses;
function mux(a:real;b:vector):vector;
function dot(a,b:vector):real;
function norm(a,b:vector):vector;
function adv(a,b:vector):vector;
function suv(a,b:vector):vector;
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
const
n=3;
var
Form1: TForm1;
r,v:array[1..n] of vector;
implementation
{$R *.dfm}
function tform1.adv(a,b:vector):vector;
begin
adv[0]:=a[0]+b[0];
adv[1]:=a[1]+b[1];
end;
function tform1.suv(a,b:vector):vector;
begin
suv[0]:=a[0]-b[0];
suv[1]:=a[1]-b[1];
end;
function tform1.mux(a:real;b:vector):vector;
begin
mux[0]:=a*b[0];
mux[1]:=a*b[1];
end;
function tform1.dot(a,b:vector):real;
begin
dot:=a[0]*b[0]+a[1]*b[1];
end;
function tform1.norm(a,b:vector):vector;
var mag,i,j:real;
begin
i:=b[0]-a[0];
j:=b[1]-a[1];
mag:=sqrt(power(i,2)+power(j,2));
if mag<>0 then begin
norm[0]:=i/mag;
norm[1]:=j/mag;
end;
end;
procedure tform1.proses;
var direction:vector;
vi,vj,swap:real;
i,j:integer;
begin
j:=2;i:=1;
direction:=norm(r[j],r[i]);//call function
vi:=dot(v[i],direction);
vj:=dot(v[j],direction);
swap:=vj-vi;
v[i]:=adv(v[i],mux(swap,direction));
v[j]:=suv(v[j],mux(swap,direction));
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
proses;
end;
end.
