在 C# 中从锯齿状数组转换为双指针 [英] Converting from a jagged array to double pointer in C#

问题描述

这里有一个简单的问题:有没有办法将锯齿状数组转换为双指针?

Simple question here: is there any way to convert from a jagged array to a double pointer?

例如将 double[][] 转换为 double**

不幸的是，这不能仅通过强制转换来完成(就像在普通的旧 C 中一样).使用 fixed 语句似乎也不能解决问题.在 C# 中是否有任何(最好是尽可能有效的)方法来实现这一点?我怀疑解决方案可能根本不是很明显，尽管我仍然希望有一个简单的解决方案.

This can't be done just by casting unfortunately (as it can in plain old C), unfortunately. Using a fixed statement doesn't seem to resolve the problem either. Is there any (preferably as efficient as possible) way to accomplish this in C#? I suspect the solution may not be very obvious at all, though I'm hoping for a straightforward one nonetheless.

推荐答案

一个 double[][] 是一个 double[] 的数组，而不是 double* 的数组，所以要得到一个 double** ，我们首先需要一个 double*[]

A double[][] is an array of double[], not of double* , so to get a double** , we first need a double*[]

double[][] array = //whatever
//initialize as necessary

fixed (double* junk = &array[0][0]){

    double*[] arrayofptr = new double*[array.Length];
    for (int i = 0; i < array.Length; i++)
        fixed (double* ptr = &array[i][0])
        {
            arrayofptr[i] = ptr;
        }

    fixed (double** ptrptr = &arrayofptr[0])
    {
        //whatever
    }
}

我不禁想知道这是为了什么，是否有比需要双指针更好的解决方案.

I can't help but wonder what this is for and if there is a better solution than requiring a double-pointer.

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