財富(儲蓄)目標算法

{* 財富目標算法                                                   *}
{*                                           p^n - 1               *}
{*     b  =  a * p^n  +  m * ----------------           *}
{*                                            p - 1                  *}
{* 說明:                                                             *}
{*     b: 財富目標    a: 初始餘額                            *}
{*     p: 1 + 年回報率 / 12                                  *}
{*     n: 儲蓄年數 * 12                                       *}
{*     m: 每月儲蓄金額                                         *}
function CalcOneEx(AValue1, AValue2: Double; AValue3:Integer;  AValue4: Double): Double;
var
  a: double;
  n: Double;
  p: Double;
  m: Double;
  b: Double;
  ltmpSum1: Double;
begin
  Result := 0.0;
  b := AValue1;
  a := AValue2;
  n := AValue3 * 12;
  p := 1+ AValue4 / 100.0 / 12 ;

 

  ltmpSum1 := a * Power(p, n); //初始餘額複利總額
  if ltmpSum1 > b then exit;

  m := (b - ltmpSum1) / ((Power(p, n) - 1) / (p - 1));

  Result := m;
end;