BigInteger.GreatestCommonDivisor(BigInteger, BigInteger) Method

Definition

Finds the greatest common divisor of two BigInteger values.

C#
public static System.Numerics.BigInteger GreatestCommonDivisor(System.Numerics.BigInteger left, System.Numerics.BigInteger right);

Parameters

left
BigInteger

The first value.

right
BigInteger

The second value.

Returns

The greatest common divisor of left and right.

Examples

The following example illustrates a call to the GreatestCommonDivisor method and the exception handling necessary to provide useful information about an ArgumentOutOfRangeException. The result indicates that the greatest common divisor of these two numbers is 1.

C#
BigInteger n1 = BigInteger.Pow(154382190, 3);
BigInteger n2 = BigInteger.Multiply(1643590, 166935);
try
{
   Console.WriteLine("The greatest common divisor of {0} and {1} is {2}.",
                     n1, n2, BigInteger.GreatestCommonDivisor(n1, n2));
}
catch (ArgumentOutOfRangeException e)
{
   Console.WriteLine("Unable to calculate the greatest common divisor:");
   Console.WriteLine("   {0} is an invalid value for {1}",
                     e.ActualValue, e.ParamName);
}

Remarks

The greatest common divisor is the largest number into which the two BigInteger values can be divided without returning a remainder.

If the left and right parameters are non-zero numbers, the method always returns at least a value of 1 because all numbers can be divided by 1. If either parameter is zero, the method returns the absolute value of the non-zero parameter. If both values are zero, the method returns zero.

Note

Computing the greatest common divisor of very large values of left and right can be a very time-consuming operation.

The value returned by the GreatestCommonDivisor method is always positive (including zero) regardless of the sign of the left and right parameters.

Applies to

Product Versions
.NET Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 1.1, 1.2, 1.3, 1.4, 1.6, 2.0, 2.1
UWP 10.0