/// <summary>
/// Calculates GCD for two or more integer numbers. Out parameter returns method execution time
/// </summary>
/// <param name="method">delegate with target method</param>
/// <param name="numberArray">input array</param>
/// <returns>great common divisor</returns>
private static int CheckConditionsAndFindGCDForTWoNumbers(GCDGetting method, params int[] numberArray)
{
if (numberArray == null)
{
throw new ArgumentNullException();
}
if (numberArray.Length < 2)
{
throw new ArgumentException();
}
List <int> numbers = new List <int>();
for (int i = 0; i < numberArray.Length; i++)
{
if (numberArray[i] == 1)
{
return(1);
}
if (numberArray[i] != 0)
{
numbers.Add(numberArray[i]);
}
}
if (numbers.Count == 0)
{
throw new ArgumentException();
}
if (numbers.Count == 1)
{
return(Math.Abs(numbers[0]));
}
int gdc = method.Invoke(numbers[0], numbers[1]);
for (int i = 2; i < numbers.Count; i++)
{
if (numbers[i] == 0)
{
continue;
}
if (gdc != 1)
{
gdc = method.Invoke(gdc, numbers[i]);
}
else
{
break;
}
}
return(gdc);
}
/// <summary>
/// Returns GCD for two or more integer numbers
/// </summary>
/// <param name="numberArray">input array of integer numbers</param>
/// <returns>great common divisor</returns>
/// <exception cref="ArgumentException"> if both parameters are zero </exception>
public static int GetSteinGCD(params int[] numberArray)
{
GCDGetting method = GetSteinGCDForTwoNumbers;
return(CheckConditionsAndFindGCDForTWoNumbers(method, numberArray));
}
