问题描述
我有课
template<size_t N, size_t M>
class Matrix {
// ....
};
我想创建一个 typedef
,它创建一个 Vector
(列向量),它等效于大小为 N 和 1 的 Matrix
.类似的东西:
I want to make a typedef
which creates a Vector
(column vector) which is equivalent to a Matrix
with sizes N and 1. Something like that:
typedef Matrix<N,1> Vector<N>;
这会产生编译错误.以下创建了类似的东西,但不完全是我想要的:
Which produces compile error. The following creates something similar, but not exactly what I want:
template <size_t N>
class Vector: public Matrix<N,1>
{ };
是否有解决方案或不太昂贵的解决方法/最佳实践?
Is there a solution or a not too expensive workaround / best-practice for it?
推荐答案
C++11新增别名声明,是typedef
的泛化,允许模板:
C++11 added alias declarations, which are generalization of typedef
, allowing templates:
template <size_t N>
using Vector = Matrix<N, 1>;
Vector<3>
类型等价于 Matrix<3, 1>
.
在 C++03 中,最接近的近似值是:
In C++03, the closest approximation was:
template <size_t N>
struct Vector
{
typedef Matrix<N, 1> type;
};
这里,类型 Vector<3>::type
等价于 Matrix<3, 1>
.
Here, the type Vector<3>::type
is equivalent to Matrix<3, 1>
.
这篇关于C++ 模板类型定义的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持编程学习网!