auto const a = make_point_2d(-1, 1);
a(2,0);
// 1. Why do I need the second index to access the elements of a Point2D?
// 2. Why can I access the element at index 2?
Which works, but is this the best way? Is there a better way to achieve what I want?
The best way depends on how you intend to use your Point2D.
If you really want Point2D and Matrix<3,1> to be the same, a possible approach is to make Point2D a type alias and write a make function to create it:
using Point2D = Matrix<3, 1>;
Point2D make_point_2d(float x, float y) { return Point2D{x, y, 1}; }
int main() {
auto const a = make_point_2d(-1, 1);
Matrix<3, 3> translate = {1, 0, 2, 0, 1, -2, 0, 0, 1};
Point2D out = translate * a;
}
To keep the design consistent, I'd introduce type aliases and make_* functions for other types too. E.g.:
This may work as long as the type aliases you need to introduce are not too many.
Edit: I'm not really sure having Point2D be (or publicly inherit from) Matrix<3,1> is a good idea. As a user, I'd be quite surprised by the fact this code would compile (and run without causing any assert to fail):
auto const a = make_point_2d(-1, 1);
a(2,0);
// 1. Why do I need the second index to access the elements of a Point2D?
// 2. Why can I access the element at index 2?
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评论（1）
最好的方法取决于您打算如何使用
Point2d。如果您真的想要
point2d和matrix＆lt; 3,1＆gt;是相同的，那么一种可能的方法是制作point2d类型别名并写入Make函数来创建它：为了保持设计一致，我会介绍类型的别名和
Make _**其他类型的功能。例如：只要您需要引入的类型别名并不多于太多，这可能会起作用。
编辑：我不确定
point2dbe（或公开继承）矩阵＆lt; 3,1＆gt;是个好主意。作为用户，我会对这个事实感到惊讶此代码将编译（并且运行而不会导致任何
断言失败）：The best way depends on how you intend to use your
Point2D.If you really want
Point2DandMatrix<3,1>to be the same, a possible approach is to makePoint2Da type alias and write amakefunction to create it:To keep the design consistent, I'd introduce type aliases and
make_*functions for other types too. E.g.:This may work as long as the type aliases you need to introduce are not too many.
Edit: I'm not really sure having
Point2Dbe (or publicly inherit from)Matrix<3,1>is a good idea. As a user, I'd be quite surprised by the factthis code would compile (and run without causing any
assertto fail):