小数点以下の数値を丸める方法は、場合により異なるため関数を作成する必要があります。
例えば、切り捨て１．５なら１にして－１．５なら－１にする関数は標準ではありません。
小数点以下を切り捨てする
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Public Shared Overloads Function RoundDown(ByVal val As Double) As Double If 0.0 < val Then return Math.Floor(val) Else return Math.Ceiling(val) End If End Function Public Shared Overloads Function RoundDown(ByVal val As Decimal) As Decimal If 0.0 < val Then return Math.Floor(val) Else return Math.Ceiling(val) End If End Function |
小数点以下を切り上する
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Public Shared Overloads Function RoundUp(ByVal val As Double) As Double If 0.0 < val Then return Math.Ceiling(val) Else return Math.Floor(val) End If End Function Public Shared Overloads Function RoundUp(ByVal val As Decimal) As Decimal If 0.0 < val Then return Math.Ceiling(val) Else return Math.Floor(val) End If End Function |
小数点以下を四捨五入する
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Public Shared Overloads Function SimpleRound(ByVal val As Double) As Double Return Math.Round(val, MidpointRounding.AwayFromZero) End Function Public Shared Overloads Function SimpleRound(ByVal val As Decimal) As Decimal Return Math.Round(val, MidpointRounding.AwayFromZero) End Function |
少数桁を指定しての丸め処理
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'少数桁を指定して小数点以下を切り捨て Public Shared Overloads Function RoundDown(ByVal val As Double, digit As short) As Double Dim d As double = Math.Pow(10.0, digit) return ((RoundDown(val * d) / d)) End Function '少数桁を指定して小数点以下を切り上 Public Shared Overloads Function RoundUp(ByVal val As Double, digit As short) As Double Dim d As double = Math.Pow(10.0, digit) return ((RoundUp(val * d) / d)) End Function '少数桁を指定して小数点以下を四捨五入 Public Shared Overloads Function SimpleRound(ByVal val As Double, digit As short) As Double Dim d As double = Math.Pow(10.0, digit) return ((SimpleRound(val * d) / d)) End Function |