对不起,如果标题和问题不清楚;我没有一个好的方式来描述它。但这里是:混淆ParamArray行为 - 重复数组以某种方式链接?
所以发生的事情是“testMat”以某种方式连接在一起,即使我没有重新定义它们,它也会使值发生变化。例如,如果你在下面运行这个代码,你会发现在testResult的matSum函数中,out1和out2的值正在改变(在循环中),我不知道为什么!它们的值在testResult1中不会改变。这种行为从何而来?
Sub Main()
Dim testMat As Double(,) = {{1, 2}, {3, 4}}
Dim testResult As Double(,) = matSum(testMat, testMat, testMat)
Dim testResult1 As Double(,) = matSum({{1, 2}, {3, 4}}, {{1, 2}, {3, 4}}, {{1, 2}, {3, 4}})
End Sub
Function matSum(ByVal ParamArray args As Double()(,)) As Double(,)
'This function sums matrices. It assumes you know how to sum matrices.
Dim m, n As Integer
Dim out, out1, out2 As Double(,)
Dim numArgs As Integer = args.Length
out = args(0)
out1 = args(1)
out2 = args(2)
m = out.GetUpperBound(0)
n = out.GetUpperBound(1)
For v As Integer = 1 To numArgs - 1
For i As Integer = 0 To m
For j As Integer = 0 To n
out(i, j) = out(i, j) + args(v)(i, j)
Next
Next
Next
Return out
End Function
数组是一个引用类型,这就是它发生的原因。它与'ParamArray'无关。 – MarcinJuraszek 2014-11-03 03:20:22
对不起,你能详细说一下吗?我以为我读到ParamArray只是ByVal? (或者这不是你指的?) – Esteban 2014-11-03 03:25:13
'ByVal',你不能改变'args'的身份(例如,你不能让'args'指向一个新的或不同的数组),但是你可以改变它的内容 - 即数组元素。 – 2014-11-03 03:33:16