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Double.CompareTo Method (Object)

Compares this instance to a specified object and returns an integer that indicates whether the value of this instance is less than, equal to, or greater than the value of the specified object.

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

public int CompareTo(
	Object value


Type: System.Object
An object to compare, or null.

Return Value

Type: System.Int32
A signed number indicating the relative values of this instance and value.



A negative integer

This instance is less than value.


This instance is not a number (NaN) and value is a number.


This instance is equal to value.


This instance and value are both Double.NaN, PositiveInfinity, or NegativeInfinity

A positive integer

This instance is greater than value.


This instance is a number and value is not a number (NaN).


value is null.




value is not a Double.

Any instance of Double, regardless of its value, is considered greater than null.

The value parameter must be null or an instance of Double; otherwise, an exception is thrown.

This method is implemented to support the IComparable interface. Note that, although a NaN is not considered to be equal to another NaN (even itself), the IComparable interface requires that A.CompareTo(A) return zero.

Precision in Comparisons

The precision of floating-point numbers beyond the documented precision is specific to the implementation and version of the .NET Framework. Consequently, a comparison of two particular numbers might change between versions of the .NET Framework because the precision of the numbers' internal representation might change.

The following code example illustrates the use of CompareTo in the context of Double.

obj1 = (Double)450;
if (a.CompareTo(obj1) < 0) 
   Console.WriteLine("{0} is less than {1}.", a.ToString(), obj1.ToString());

if (a.CompareTo(obj1) > 0) 
   Console.WriteLine("{0} is greater than {1}.", a.ToString(), obj1.ToString());

if (a.CompareTo(obj1) == 0) 
   Console.WriteLine("{0} equals {1}.", a.ToString(), obj1.ToString());

.NET Framework

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

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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