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git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@7886 8e941d3f-bd1b-0410-a28a-d453659cc2b4
103 lines
2.5 KiB
ObjectPascal
103 lines
2.5 KiB
ObjectPascal
unit SumYrsDepUnit;
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{$mode objfpc}{$H+}
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interface
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uses
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Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs,
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StdCtrls, Math, contexthelpunit;
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type
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{ TSumYrsDepFrm }
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TSumYrsDepFrm = class(TForm)
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HelpBtn: TButton;
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ResetBtn: TButton;
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ComputeBtn: TButton;
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ReturnBtn: TButton;
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CostEdit: TEdit;
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SalvageEdit: TEdit;
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LifeEdit: TEdit;
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PeriodEdit: TEdit;
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DepreciationEdit: TEdit;
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Label1: TLabel;
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Label2: TLabel;
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Label3: TLabel;
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Label4: TLabel;
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Label5: TLabel;
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procedure ComputeBtnClick(Sender: TObject);
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procedure FormShow(Sender: TObject);
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procedure HelpBtnClick(Sender: TObject);
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procedure ResetBtnClick(Sender: TObject);
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private
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{ private declarations }
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function SYDDepreciation(Cost, Salvage: Extended; Life, Period: Integer): Extended;
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public
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{ public declarations }
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end;
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var
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SumYrsDepFrm: TSumYrsDepFrm;
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implementation
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{ TSumYrsDepFrm }
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procedure TSumYrsDepFrm.ResetBtnClick(Sender: TObject);
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begin
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CostEdit.Text := '';
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SalvageEdit.Text := '';
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LifeEdit.Text := '';
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DepreciationEdit.Text := '';
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PeriodEdit.Text := '';
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end;
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procedure TSumYrsDepFrm.ComputeBtnClick(Sender: TObject);
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VAR
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Cost, Depreciation, Salvage : Extended;
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Life, Period : integer;
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begin
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Cost := StrToFloat(CostEdit.Text);
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Salvage := StrToFloat(SalvageEdit.Text);
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Life := StrToInt(LifeEdit.Text);
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Period := StrToInt(PeriodEdit.Text);
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Depreciation := SYDDepreciation(Cost, Salvage, Life, Period);
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DepreciationEdit.Text := FloatToStr(Depreciation);
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end;
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procedure TSumYrsDepFrm.FormShow(Sender: TObject);
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begin
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ResetBtnClick(self);
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end;
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procedure TSumYrsDepFrm.HelpBtnClick(Sender: TObject);
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begin
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ContextHelpForm.HelpMessage((Sender as TButton).tag);
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end;
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function TSumYrsDepFrm.SYDDepreciation(Cost, Salvage: Extended; Life, Period: Integer): Extended;
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{ SYD = (cost - salvage) * (life - period + 1) / (life*(life + 1)/2) }
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{ Note: life*(life+1)/2 = 1+2+3+...+life "sum of years"
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The depreciation factor varies from life/sum_of_years in first period = 1
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downto 1/sum_of_years in last period = life.
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Total depreciation over life is cost-salvage.}
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var
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X1, X2: Extended;
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begin
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Result := 0;
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if (Period < 1) or (Life < Period) or (Cost <= Salvage) then Exit;
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X1 := 2 * (Life - Period + 1);
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X2 := Life * (Life + 1);
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Result := (Cost - Salvage) * X1 / X2
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end;
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initialization
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{$I sumyrsdepunit.lrs}
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end.
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