Приклад побудови графіка експоненціальної функції

Графік функції  

Код мовою Pascal

unit Unit1;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, ExtCtrls, jpeg;

type

  TForm1 = class(TForm)

    PaintBox1: TPaintBox;

    Image1: TImage;

    procedure PaintBox1Click(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

implementation

{$R *.dfm}

function f(x:real):real;

begin

  f:=exp(x);

end;

procedure TForm1.PaintBox1Click(Sender: TObject);

var x,y,xp,xk:real;

    i,sx,sy:integer;

begin

    sx:=160;

    sy:=360;

    xp:=-9;

    xk:=9;

    PaintBox1.Canvas.Pen.Color:=clGray;

    for i := 0 to 9 do begin

        PaintBox1.Canvas.MoveTo(i*40,0);

        PaintBox1.Canvas.LineTo(i*40,400);

    end;

    for i := 0 to 9 do begin

        PaintBox1.Canvas.MoveTo(0,i*40);

        PaintBox1.Canvas.LineTo(400,i*40);

    end;

    PaintBox1.Canvas.Pen.Color:=clBlack;

    PaintBox1.Canvas.Pen.Width:=3;

    //

    PaintBox1.Canvas.MoveTo(sx-1,0);

    PaintBox1.Canvas.LineTo(sx-1,400);

    //

    PaintBox1.Canvas.MoveTo(0,sy-1);

    PaintBox1.Canvas.LineTo(400,sy-1);

    //

    PaintBox1.Canvas.MoveTo(sx-6,10);

    PaintBox1.Canvas.LineTo(sx-1,0);

    PaintBox1.Canvas.MoveTo(sx+4,10);

    PaintBox1.Canvas.LineTo(sx-1,0);

    //

    PaintBox1.Canvas.MoveTo(390,sy-5);

    PaintBox1.Canvas.LineTo(400,sy-1);

    PaintBox1.Canvas.MoveTo(390,sy+4);

    PaintBox1.Canvas.LineTo(400,sy-1);

    PaintBox1.Canvas.Font.Size :=12;

    PaintBox1.Canvas.TextOut(sx-15,10,'Y');

    PaintBox1.Canvas.TextOut(sx-15,10+sy-60,'1');

    PaintBox1.Canvas.TextOut(sx-15,sy+3,'0');

    PaintBox1.Canvas.TextOut(sx+36,sy+3,'1');

    PaintBox1.Canvas.TextOut(380,sy+3,'X');

    PaintBox1.Canvas.Pen.Color:=clRed;

    PaintBox1.Canvas.Pen.Width:=2;

    PaintBox1.Canvas.MoveTo(round(40*xp+sx),round(sy-40*f(xp)));

    x:=xp;

    while x<xk do begin

      y:=f(x);

      PaintBox1.Canvas.LineTo(round(40*x+sx),round(sy-40*y));

      x:=x+0.1;

    end;

end;

end.