当我改变一个多维数组的值时，另一个数组相同位置的值也会改变.为什么?
本文关键字：数组 改变 另一个 位置 为什么 一个 | 更新日期: 2023-09-27 18:27:57
我花了很多时间才弄清楚这一点。
我有2个多维数组：
int[,] OldGeneration = new int[WidthX + 1, HeightY + 1];
int[,] NextGeneration = new int[WidthX + 1, HeightY + 1];
稍后在我的代码中，在"下一代"中设置了一些值后，我使数组包含相同的值。
OldGeneration = NextGeneration;
当我在运行程序时检查这些值时，它正在工作。
稍低一点，然后我更改"下一代"的一个值，当我这样做时，"旧一代"中的相同值也将更改。
你能告诉我为什么吗？
using System;
namespace CGoL
{
class CGoL_Base
{
static void Main(string[] args)
{
//Declare and define (initialize) Variables used by the Program
int WidthX = 5, HeightY = 5, Iterations = 5, Speed = 1000, Random = 0, CellsAlive = 0;
//Declare Multidimensional Arrays for actual generation and next generation
int[,] OldGeneration = new int[WidthX + 1, HeightY + 1];
int[,] NextGeneration = new int[WidthX + 1, HeightY + 1];
//########### Initialize "Game Board" ##########################
//Set Game Board to contain only dead cells
for (int y = 1; y <= HeightY; y++)
{
for (int x = 1; x <= WidthX; x++)
{
NextGeneration[x, y] = 0;
}
}
//Set pattern for oscillating (moving) structure with 3 living cells (Can be changed at will)
NextGeneration[3, 2] = 1;
NextGeneration[3, 3] = 1;
NextGeneration[3, 4] = 1;
//Set OldGeneration equal with NextGeneration so that the calculation can work
OldGeneration = NextGeneration;
//##################################################################
//Start the iterationcounter
for (int Iteration = 1; Iteration <= Iterations; Iteration++)
{
//########### Calculate actual generation ######################
//Calculate how the Game Board will change with the usual CGoL rules
if (Iteration >= 2) //Without this, the initialization above will not work
{
for (int y = 1; y <= HeightY; y++)
{
for (int x = 1; x <= WidthX; x++)
{
//########### Check surrounding Cells ##########################
//Check how much cells, surrounding the actual cell, are still alive
//to calculate later how the Game Board will change
CellsAlive = 0;
for (int i = -1; i <= 1; i++)
{
for (int n = -1; n <= 1; n++)
{
if (i == 0 && n == 0)
{
continue;
}
//Check if some Array Index will be out of Array Range (for example when index is smaller than 0)
if (x + n == 0 || x + n > WidthX || y + i == 0 || y + i > HeightY)
{
continue;
}
if (OldGeneration[(x + n), (y + i)] == 1)
{
CellsAlive++;
}
}
}
//##################################################################
//If a dead cell got 3 living neighbours, the cell will become alive in the next generation
if (OldGeneration[x, y] == 0 && CellsAlive == 3)
{
NextGeneration[x, y] = 1;
}
//If a living cell got less than 2 living neighbours, the cell will die in the next generation
else if (OldGeneration[x, y] == 1 && CellsAlive < 2)
{
NextGeneration[x, y] = 0; //OldGeneration[x, y] will be changed to 0 even if it is not written here????? why?
}
//If a living cell got 2 or 3 living neighbours, the cell will stay alive in the next generation
else if (OldGeneration[x, y] == 1 && (CellsAlive == 2 || CellsAlive == 3))
{
NextGeneration[x, y] = 1;
}
//If a living cell got more than 3 living neighbours, the cell will die in the next generation
else if (OldGeneration[x, y] == 1 && CellsAlive > 3)
{
NextGeneration[x, y] = 0;
}
}
}
Console.ReadKey();
}
//##################################################################
//########### Draw the "Game Board" ############################
//Makes the console window Empty :)
Console.Clear();
//"for" is making new rows with Console.Write("'n");
for (int y = 1; y <= HeightY; y++)
{
//"for" is writing "O"'s in one row
for (int x = 1; x <= WidthX; x++)
{
if (NextGeneration[x, y] == 1)
{
Console.Write("O ");
}
else
{
Console.Write(" ");
}
}
Console.Write("'n");
}
Console.WriteLine("Iteration: {0}", Iteration);
System.Threading.Thread.Sleep(Speed);
//At the end, make the actual generation same like the old generation to be calculated next
OldGeneration = NextGeneration;
//##################################################################
}
Console.ReadKey();
}
}
}
当您声明：
OldGeneration = NextGeneration;
您将NextGeneration的引用分配给OldGeneration，因此您对其中一个所做的任何更改都会反映到另一个，这是正常的。
如果要制作不相交的副本，则应使用Array.Copy（http://msdn.microsoft.com/it-it/library/y5s0whfd（v=vs.110）.aspx）
这一行就是问题所在：OldGeneration = NextGeneration;
在这行之前有两个对象（两个数组），在这行之后有一个对象，两个变量都可以查看。您必须在双循环中复制内容，而不是上面的行。
这是因为您没有使数组包含相同的值，所以您将一个数组的引用替换为对另一个阵列的引用。
从那时起，两个变量都引用相同的数组。当您使用一个变量更改数组时，当您使用另一个变量查看数组时，更改将是可见的，因为它是同一个数组。
如果要将数据从一个数组复制到另一个数组，可以使用Array.Copy方法：
Array.Copy(NextGeneration, OldGeneration, NextGeneration.Length);
使用此行：
OldGeneration = NextGeneration;
使OldGeneration变量引用与NextGeneration变量相同的内存。
你可以复制数组：
Array.Copy(NextGeneration, OldGeneration, NextGeneration.Length);