Math.IEEERemainder Method (System)

IEEERemainder Method

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Microsoft Visual Studio 11/.NET Framework 4.5

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.NET Framework Class Library

Math..::.IEEERemainder Method

[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]

Returns the remainder resulting from the division of a specified number by another specified number.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic

Public Shared Function IEEERemainder ( _
	x As Double, _
	y As Double _
) As Double

public static double IEEERemainder(
	double x,
	double y
)

Visual C++

public:
static double IEEERemainder(
	double x, 
	double y
)

static member IEEERemainder : 
        x:float * 
        y:float -> float

Parameters

x: Type: System..::.Double
A dividend.

y: Type: System..::.Double
A divisor.

Return Value

Type: System..::.Double
A number equal to x - (y Q), where Q is the quotient of x / y rounded to the nearest integer (if x / y falls halfway between two integers, the even integer is returned).If x - (y Q) is zero, the value +0 is returned if x is positive, or -0 if x is negative.If y = 0, NaN is returned.

Remarks

This operation complies with the remainder operation defined in Section 5.1 of ANSI/IEEE Std 754-1985; IEEE Standard for Binary Floating-Point Arithmetic; Institute of Electrical and Electronics Engineers, Inc; 1985.

The IEEERemainder method is not the same as the modulus operator. Although both return the remainder after division, the formulas they use are different. The formula for the IEEERemainder method is:

IEEERemainder = dividend - (divisor * Math.Round(dividend / divisor))

In contrast, the formula for the modulus operator is:

Modulus = (Math.Abs(dividend) - (Math.Abs(divisor) * 
          (Math.Floor(Math.Abs(dividend) / Math.Abs(divisor))))) * 
          Math.Sign(dividend)

Examples

The following example contrasts the remainder returned by the IEEERemainder method with the remainder returned by the modulus division operator.

Visual Basic

Module Example
   Public Sub Main()
      Console.WriteLine("{0,35} {1,20}", "IEEERemainder", "Modulus")
      ShowRemainders(3, 2)
      ShowRemainders(4, 2)
      ShowRemainders(10, 3)
      ShowRemainders(11, 3)
      ShowRemainders(27, 4)
      ShowRemainders(28, 5)
      ShowRemainders(17.8, 4)
      ShowRemainders(17.8, 4.1)
      ShowRemainders(-16.3, 4.1)
      ShowRemainders(17.8, -4.1)
      ShowRemainders(-17.8, -4.1)
   End Sub

   Private Sub ShowRemainders(number1 As Double, number2 As Double)
      Dim formula As String = String.Format("{0} / {1} = ", number1, number2)
      Console.WriteLine("{0,-16} {1,18} {2,20}", _
                       formula, _
                       Math.IEEERemainder(number1, number2), _
                       number1 Mod number2)  
   End Sub
End Module
' The example displays the following output:
'       
'                             IEEERemainder              Modulus
'       3 / 2 =                          -1                    1
'       4 / 2 =                           0                    0
'       10 / 3 =                          1                    1
'       11 / 3 =                         -1                    2
'       27 / 4 =                         -1                    3
'       28 / 5 =                         -2                    3
'       17.8 / 4 =                      1.8                  1.8
'       17.8 / 4.1 =                    1.4                  1.4
'       -16.3 / 4.1 =    0.0999999999999979                   -4
'       17.8 / -4.1 =                   1.4                  1.4
'       -17.8 / -4.1 =                 -1.4                 -1.4

using System;

public class Example
{
   public static void Main()
   {
      Console.WriteLine("{0,35} {1,20}", "IEEERemainder", "Modulus");
      ShowRemainders(3, 2);
      ShowRemainders(4, 2);
      ShowRemainders(10, 3);
      ShowRemainders(11, 3);
      ShowRemainders(27, 4);
      ShowRemainders(28, 5);
      ShowRemainders(17.8, 4);
      ShowRemainders(17.8, 4.1);
      ShowRemainders(-16.3, 4.1);
      ShowRemainders(17.8, -4.1);
      ShowRemainders(-17.8, -4.1);
   }

   private static void ShowRemainders(double number1, double number2)
   {
      string formula = String.Format("{0} / {1} = ", number1, number2);
      Console.WriteLine("{0,-16} {1,18} {2,20}", 
                       formula, 
                       Math.IEEERemainder(number1, number2), 
                       number1 % number2);  
   }
}
// The example displays the following output:
//       
//                             IEEERemainder              Modulus
//       3 / 2 =                          -1                    1
//       4 / 2 =                           0                    0
//       10 / 3 =                          1                    1
//       11 / 3 =                         -1                    2
//       27 / 4 =                         -1                    3
//       28 / 5 =                         -2                    3
//       17.8 / 4 =                      1.8                  1.8
//       17.8 / 4.1 =                    1.4                  1.4
//       -16.3 / 4.1 =    0.0999999999999979                   -4
//       17.8 / -4.1 =                   1.4                  1.4
//       -17.8 / -4.1 =                 -1.4                 -1.4

Version Information

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Platforms

Windows 8 Release Preview, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 SP2, Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Reference

Math Class

System Namespace