返回一个int数组在C ++中 [英] Return a float array in C++

问题描述

我目前在C ++的一个4x4矩阵类，我存储每个值作为浮动：

I currently have a 4x4 matrix class in C++ and I store each value as a float:

Matrix4d::Matrix4d(const float& m00, const float& m01, const float& m02, const float& m03,
                   const float& m10, const float& m11, const float& m12, const float& m13,
                   const float& m20, const float& m21, const float& m22, const float& m23,
                   const float& m30, const float& m31, const float& m32, const float& m33)
{
    _m00 = m00;
    _m01 = m01;
    _m02 = m02;
    _m03 = m03;
    _m10 = m10;
    _m11 = m11;
    _m12 = m12;
    _m13 = m13;
    _m20 = m20;
    _m21 = m21;
    _m22 = m22;
    _m23 = m23;
    _m30 = m30;
    _m31 = m31;
    _m32 = m32;
    _m33 = m33;
}

我的问题是，我怎么可以把这些信息返回的float数组？我没有问题，建立在类数组例如：

My question is, how can I return a float array of this data? I have no problem creating the array in the class for example:

float arrayToReturn[16] = { m00, m01, m02, m03, ... m33 };

不过，我不能从类返回此值。我读过有关的指针返回数组，但没有运气吧。

However I can not return this value from the class. I've read about returning a pointer to the array, but have had no luck with it.

推荐答案

如果您的内部数组看起来像 int数组这会工作[4] [4] ：

This would work if your internal array looked like float array[4][4]:

float** Matrix4d::getMatrix();

如果您的内部数组是一维数组：

If your internal array was a one-dimensional array:

float* Matrix4d::getMatrix();

不过，这两种情况下暴露你的类的内部工作到外面的世界，有使你的code更不安全和难以维护。

But both cases expose the internal workings of your class to the outside world, with makes your code less safe and harder to maintain.

这将是最好创建一个拷贝构造函数，一个（）运营商，并赋值运算符为​​你Matrix4d类，只是通过周围。你会不太可能有运行时错误是由于坏的内存管理或数据损坏。

It would be better to create a copy constructor, a () operator, and an assignment operator for your Matrix4d class and just pass that around. You'd be less likely to have runtime errors due to bad memory management or data corruption.

您（）运营商应该是这样的：

Your () operator would look like this:

float& operator()( unsigned int xIndex, unsigned int yIndex )
{
  //return the right attribute
}

您会这样称呼它为设定值：

You would call it like this for setting values:

aMatrix(0,0) = 2.0;

或本检索：

float attributeCopy = aMatrix(0,0);

这两种方式都可以。

It works both ways.

编辑：忘了 [] 运营商只用了一个参数。改变了运营商的（）运营商a.k.a功能运营商。

Forgot that the [] operator only took one argument. Changed the operator to the () operator a.k.a the functional operator.

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