static void Main(string[] args)
{
//创建二维数组[2004...2009][1...4]
int[] lowerBounds = { 2005, 1 };
int[] lengths = { 5, 4 };
decimal[,] quarterlyRevenue = (decimal[, ])Array.CreateInstance(typeof(decimal), lengths, lowerBounds);
Console.WriteLine("{0,4} {1,9} {2,9} {3,9} {4,9}", "Year", "Q1", "Q2", "Q3", "Q4");
int firstYear = quarterlyRevenue.GetLowerBound(0);
int lastYear = quarterlyRevenue.GetUpperBound(0);
int firstQuarter = quarterlyRevenue.GetLowerBound(1);
int lastQuarter = quarterlyRevenue.GetUpperBound(1);
for (int year = firstYear; year <= lastYear; year++)
{
Console.Write(year + " ");
for (int quarter = firstQuarter; quarter <= lastQuarter; quarter++)
{
Console.Write("{0,9:C}", quarterlyRevenue[year, quarter]);
}
Console.WriteLine();
}
Console.ReadLine();
}
public NMatrix(decimal[,] data)
{
Data = data;
Rows = Data.GetUpperBound(0) - Data.GetLowerBound(0) + 1;
Columns = Data.GetUpperBound(1) - Data.GetLowerBound(1) + 1;
}
static void Main(string[] args)
{
int[] lowerBounds = { 2005, 1 };
int[] lengths = { 5, 4 };
//利用Array类型的静态方法，可以创建下标起始不为0的数组
decimal[,] quarterlyRevenue = (decimal[, ])Array.CreateInstance(typeof(decimal), lengths, lowerBounds);
Console.WriteLine("{0,4}{1,9}{2,9}{3,9}{4,9}", "Year", "Q1", "Q2", "Q3", "Q4");
int firstYear = quarterlyRevenue.GetLowerBound(0);
int lastYear = quarterlyRevenue.GetUpperBound(0);
int firstQ = quarterlyRevenue.GetLowerBound(1);
int lastQ = quarterlyRevenue.GetUpperBound(1);
for (int year = firstYear; year <= lastYear; year++)
{
Console.Write(year + " ");
for (int quarter = firstQ; quarter <= lastQ; quarter++)
{
Console.Write("{0, 9:C}", quarterlyRevenue[year, quarter]);
}
Console.WriteLine();
}
Console.ReadKey();
}
/// <summary>
/// This method finds the smallest value in the given distance array. If the smallest value appears more than once,
/// then the lower index is returned.
/// </summary>
/// <param name="distances">The pre-calculated distance matrix.</param>
/// <returns>The first smallest distance index.</returns>
public static int[] FirstSmallestDistanceIndex(decimal[,] distances)
{
if (ParameterValidation.IsDecimalArrayNullOrEmpty(distances))
{
return(null);
}
var indexSmallest = new[] { 0, 0 };
//var indexSmallestA = 0;
//var indexSmallestB = 0;
for (int indexA = distances.GetLowerBound(0); indexA <= distances.GetUpperBound(0); indexA++)
{
for (int indexB = distances.GetLowerBound(1); indexB <= distances.GetUpperBound(1); indexB++)
{
if ((indexA != indexB) && ((indexSmallest[0] == indexSmallest[1]) || (Math.Abs(distances[indexA, indexB]) < Math.Abs(distances[indexSmallest[0], indexSmallest[1]]))))
{
indexSmallest[0] = indexA;
indexSmallest[1] = indexB;
}
}
}
return(indexSmallest); // new int[] { indexSmallestA, indexSmallestB };
}
/// <summary>
/// This method finds the next smallest value in the array, after the value found in the index specified. If the same
/// value exists multiple times, the lower index is returned.
/// </summary>
/// <param name="distances">The pre-calculated distance matrix.</param>
/// <param name="indexLast"></param>
/// <returns>The next smallest distance index from the last indexes.</returns>
public static int[] NextSmallestDistanceIndex(decimal[,] distances, int[] indexLast)
{
if (ParameterValidation.IsDecimalArrayNullOrEmpty(distances))
{
throw new ArgumentOutOfRangeException(nameof(distances));
}
if (ParameterValidation.IsIntArrayNullOrEmpty(indexLast))
{
throw new ArgumentOutOfRangeException(nameof(indexLast));
}
var indexBest = new[] { -1, -1 };
//var indexBestA = -1;
//var indexBestB = -1;
if ((indexLast[0] == -1) || (indexLast[1] == -1))
{
return(FirstSmallestDistanceIndex(distances));
}
for (int indexA = distances.GetLowerBound(0); indexA <= distances.GetUpperBound(0); indexA++)
{
for (int indexB = distances.GetLowerBound(1); indexB <= distances.GetUpperBound(1); indexB++)
{
if
//// Not the same object twice / no distance measurement ... zero.
((indexA != indexB)
&&
//// Not the same indexes the other way around as last time (at least one value changed).
(indexLast[0] != indexB || indexLast[1] != indexA)
&&
//// Not the same indexes the same way around as last time (at least one value changed).
(indexLast[0] != indexA || indexLast[1] != indexB)
&&
//// Distance can be the same as the last one - if the index is higher.
((Math.Abs(distances[indexA, indexB]) == Math.Abs(distances[indexLast[0], indexLast[1]]) && (indexA > indexLast[0] || (indexA >= indexLast[0] && indexB > indexLast[1])))
||
//// Distance can be more, but only if it is less than the best found so far.
(Math.Abs(distances[indexA, indexB]) > Math.Abs(distances[indexLast[0], indexLast[1]]) && (indexBest[0] == -1 || indexBest[1] == -1 || Math.Abs(distances[indexA, indexB]) < Math.Abs(distances[indexBest[0], indexBest[1]])))))
{
indexBest[0] = indexA;
indexBest[1] = indexB;
if (distances[indexA, indexB] == distances[indexLast[0], indexLast[1]])
{
// If the distance is the same, then it is impossible to find a lower one, so break out, also, if no break, indexes may be skipped.
break;
}
}
}
}
return(indexBest); //new int[] { indexBestA, indexBestB };
}
protected static double[,] DecimalsToDoubles(decimal[,] array)
{
int rows = array.GetUpperBound(0) - array.GetLowerBound(0) + 1;
int cols = array.GetUpperBound(1) - array.GetLowerBound(1) + 1;
double[,] result = new double[rows, cols];
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < cols; j++)
{
result[i, j] = (double)array[i, j];
}
}
return(result);
}
public static void MainTestArray()
{
var names = new[] { 1, 2, 0, 5, 4 };
var namesdes = new int[names.Length];
System.Buffer.BlockCopy(names, 0, namesdes, 1, names.Length);
var des = new string[namesdes.Length];
foreach (var val in namesdes)
{
//Console.WriteLine(val);
}
var arr = new object[10];
var arrs = new object[10, 8];
//Console.WriteLine(namesdes.Aggregate((a, b) => a.ToString() + "," + b.ToString()));
//Console.WriteLine(FileAttributes.Archive | FileAttributes.Hidden | FileAttributes.Normal);
//Console.WriteLine(FileAttributes.Archive & FileAttributes.Archive);
decimal[,] darr = (decimal[, ])Array.CreateInstance(typeof(decimal), new int[] { 5, 4 }, new[] { 2005, 1 });
Console.WriteLine("{0,4},{1,9},{2,9},{3,9},{4,9}", "Year", "Q1", "Q2", "Q3", "Q4");
int firstYear = darr.GetLowerBound(0);
int lastYear = darr.GetUpperBound(0);
int firstQuarter = darr.GetLowerBound(1);
int lastQuarter = darr.GetUpperBound(1);
for (int i = firstYear; i <= lastYear; i++)
{
Console.Write(i + " ");
for (int j = firstQuarter; j <= lastQuarter; j++)
{
Console.Write("{0,1:C} ", darr[i, j]);
}
Console.WriteLine();
}
int[,] a1 = new int[10000, 10000];
int[][] a2 = new int[10000][];
for (int i = 0; i < 10000; i++)
{
a2[i] = new int[10000];
}
Stopwatch sw = Stopwatch.StartNew();
for (int i = 0; i < 10; i++)
{
Safe2DimArrayAccess(a1);
}
Console.WriteLine("{0}:Safe2DimArrayAccess", sw.Elapsed);
sw = Stopwatch.StartNew();
for (int i = 0; i < 10; i++)
{
SafeJaggedArrayAccess(a2);
}
Console.WriteLine("{0}:SafeJaggedArrayAccess", sw.Elapsed);
sw = Stopwatch.StartNew();
for (int i = 0; i < 10; i++)
{
UnSafe2DimArrayAccess(a1);
}
Console.WriteLine("{0}:UnSafe2DimArrayAccess", sw.Elapsed);
StackallocDemo();
InlineArrayDemo();
Console.Read();
}
