uses Math;
function RoundToEx(const AValue: Double; const ADigit: TRoundToRange; AFlag: Boolean): Double;
var
LFactor: Double;
begin
LFactor := IntPower(10, ADigit);
if AFlag then
Result := Round(AValue / LFactor) * LFactor //需要四舍五入
else
Result := Trunc (AValue / LFactor) * LFactor; //不需要四舍五入!!!
end;
//使用方法
procedure TForm1.Button1Click(Sender: TObject);
var
s: Double;
begin
s :=RoundToEx(2.48, -1, False); // -1 代表保留一位小數, False 為不需要四舍五入
ShowMessage( formatfloat('#.#', s)); // 顯示格式: #.### 顯示3位小數,而且取決 S;
end;
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