C# | Math.IEEERemainder() Method

In C#, IEEERemainder() is a Math class method which is used to return the remainder resulting from the division of a specified number by another specified number.

Syntax: 

public static double IEEERemainder (double a, double b);

Parameters: 

a: It is the dividend of type System.Double.
b: It is the divisor of type System.Double. 
 

Return Type: This method returns a number equal to a - (b Q), where Q is the quotient of a / b rounded to the nearest integer of type System.Double.

Note: 

• If a / b falls halfway between two integers, the even integer is returned.
• If a - (b Q) is zero, the value Positive Zero is returned if a is positive, or Negative Zero if a is negative.
• If b = 0, NaN is returned.

Difference Between IEEERemainder and Remainder Operator: Both are used to returns the remainder after division but the formulas they use are different. The formula for the IEEERemainder method is: 

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

And the formula for the remainder operator is: 

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

Example: 

Output:  

 IEEERemainder Remainder Operator
0 / 1 = 0 0
-4 / 8 = -4 -4
1 / 0 = NaN NaN
-1 / 0 = NaN NaN
145 / 7 = -2 5
18.52 / 2 = 0.52 0.52
42.26 / 4.2 = 0.259999999999998 0.259999999999996

Reference: https://learn.microsoft.com/en-us/dotnet/api/system.math.ieeeremainder?view=netframework-4.7.2