/// <summary>
/// Method that calculates GCD for any number of integer values.
/// </summary>
/// <param name="option">
/// defines calculation algorithm(Euclidean, Stein).
/// </param>
/// <param name="integers">
/// params int[].
/// </param>
/// <returns>
/// GCD for params int[].
/// </returns>
public static int GetGCD(AlgOption option, params int[] integers)
{
int gcd = integers[0];
for (int i = 1; i < integers.Length; i++)
{
if (integers[i] == 0 && gcd == 0)
{
continue; // skips iteration if both arguments are zero
}
if (option == 0)
{
gcd = GetGCDForTwo(gcd, integers[i]);
}
else
{
gcd = GetGCDForTwoBinary(gcd, integers[i]);
}
}
// if all arguments are zero gcd cannot be calculated (infinity?)
if (gcd == 0)
{
throw new ArgumentException(message: "GCD cannot be calculated if all numbers are 0");
}
return(gcd);
}
/// <summary>
/// Overloaded version of method designed to calculate runtime for given algorithm.
/// </summary>
/// <param name="option">
/// defines calculation algorithm(Euclidean, Stein).
/// </param>
/// <param name="time">
/// returns runtime(out).
/// </param>
/// <param name="integers">
/// params int[].
/// </param>
/// <returns>
/// GCD.
/// </returns>
public static int GetGCD(AlgOption option, out int time, params int[] integers)
{
var watch = new Stopwatch();
int firstRun = GetGCDForTwo(187, 319);
firstRun = GetGCDForTwoBinary(187, 319);
watch.Start();
int gcd = 0;
// algorithms take less than millisecond.
// in order to calculate runtime it runs algorithm a million times.
for (int j = 0; j < 1000000; j++)
{
gcd = integers[0];
for (int i = 1; i < integers.Length; i++)
{
if (integers[i] == 0 && gcd == 0)
{
continue;
}
if (option == 0)
{
gcd = GetGCDForTwo(gcd, integers[i]);
}
else
{
gcd = GetGCDForTwoBinary(gcd, integers[i]);
}
}
if (gcd == 0)
{
throw new ArgumentException(message: "GCD cannot be calculated if all numbers are 0");
}
}
watch.Stop();
time = (int)watch.ElapsedMilliseconds;
return(gcd);
}