delphi 帮助里的 RoundTo 的帮助

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Rounds a floating-point value to a specified digit or power of ten using 揃anker抯 rounding?

Unit

Math

Category

Arithmetic routines

type TRoundToRange = -37..37;
function RoundTo(const AValue: Double; const ADigit: TRoundToRange): Double;

Description

Call RoundTo to round AValue to a specified power of ten.

AValue is the value to round.

ADigit indicates the power of ten to which you want AValue rounded. It can be any value from ?7 to 37 (inclusive).

RoundTo uses 揃anker抯 Rounding?to determine how to round values that are exactly midway between the two values that have the desired number of significant digits. This method rounds to an even number in the case that AValue is not nearer to either value.

The following examples illustrate the use of RoundTo:

Expression Value

RoundTo(1234567, 3) 1234000
RoundTo(1.234, -2) 1.23
RoundTo(1.235, -2) 1.24
RoundTo(1.245, -2) 1.24

Note: The behavior of RoundTo can be affected by the Set8087CW procedure or SetRoundMode function.