# Math.IEEERemainder Method

.NET Framework 4.5

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

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

## Syntax

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

#### 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.

```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

#### .NET for Windows Store apps

Supported in: Windows 8

#### .NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

## Platforms

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), 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.