How to properly compare decimal values in C#?

Question

I come from a background in C++, and I know that you cannot accurately compare floats for equality. For C#, I simply assumed the same policy applies to decimal values, or an

Answer 1

I was investigating something similar, but with a precision instead of a margin of error and ended up writing some extensions for Float. This can easily be adapted for any type though. I've got a complicated series of comparisons and this makes it nice and readable.

/// 

/// A set of extensions to allow the convenient comparison of float values based on a given precision.
/// 
public static class FloatingPointExtensions
{
    /// 

    /// Determines if the float value is less than or equal to the float parameter according to the defined precision.
    /// 
    /// The float1.
    /// The float2.
    /// The precision.  The number of digits after the decimal that will be considered when comparing.
    /// 
    public static bool LessThan(this float float1, float float2, int precision)
    {
        return (System.Math.Round(float1 - float2, precision) < 0);
    }

    /// 

    /// Determines if the float value is less than or equal to the float parameter according to the defined precision.
    /// 
    /// The float1.
    /// The float2.
    /// The precision.  The number of digits after the decimal that will be considered when comparing.
    /// 
    public static bool LessThanOrEqualTo(this float float1, float float2, int precision)
    {
        return (System.Math.Round(float1 - float2, precision) <= 0);
    }

    /// 

    /// Determines if the float value is greater than (>) the float parameter according to the defined precision.
    /// 
    /// The float1.
    /// The float2.
    /// The precision.  The number of digits after the decimal that will be considered when comparing.
    /// 
    public static bool GreaterThan(this float float1, float float2, int precision)
    {
        return (System.Math.Round(float1 - float2, precision) > 0);
    }

    /// 

    /// Determines if the float value is greater than or equal to (>=) the float parameter according to the defined precision.
    /// 
    /// The float1.
    /// The float2.
    /// The precision.  The number of digits after the decimal that will be considered when comparing.
    /// 
    public static bool GreaterThanOrEqualTo(this float float1, float float2, int precision)
    {
        return (System.Math.Round(float1 - float2, precision) >= 0);
    }

    /// 

    /// Determines if the float value is equal to (==) the float parameter according to the defined precision.
    /// 
    /// The float1.
    /// The float2.
    /// The precision.  The number of digits after the decimal that will be considered when comparing.
    /// 
    public static bool AlmostEquals(this float float1, float float2, int precision)
    {
        return (System.Math.Round(float1 - float2, precision) == 0);
    } 
}