举例:
System 单元下的公用函数目录
var i: Integer; d: Real; begin i := Trunc(1234.5678); {截取整数} ShowMessage(IntToStr(i)); {1234} i := Trunc(-1234.5678); ShowMessage(IntToStr(i)); {-1234} i := Round(1234.5678); {...} ShowMessage(IntToStr(i)); {1235} i := Round(-1234.5678); ShowMessage(IntToStr(i)); {-1235} {Int 和 Trunc 都是向 0 方向舍入, 貌似结果一直, 但它们返回的类型不一样} {Trunc 返回的是 Int64; Int 返回的是 Extended 类型} d := Int(1234.5678); ShowMessage(FloatToStr(d)); {1234} d := Int(-1234.5678); ShowMessage(FloatToStr(d)); {-1234} end; //四舍五入函数: System.Math.SimpleRoundTo uses System.Math; procedure TForm1.FormCreate(Sender: TObject); var f, f1,f2: Double; begin f := 2.5555555; f1 := SimpleRoundTo(f); //2.56 f2 := SimpleRoundTo(f, -3); //2.556 ShowMessageFmt('%g, %g, %g', [f, f1, f2]); end;
System 单元下的公用函数目录