C++ 我做错了什么?或者这是一个叮当声++;缺陷
以下代码无法在我的Mac上编译C++ 我做错了什么?或者这是一个叮当声++;缺陷,c++,macos,clang++,C++,Macos,Clang++,以下代码无法在我的Mac上编译 #include <iostream> #include <array> template <typename T, unsigned int N> using Vector = std::array<T, N>; template <typename T, unsigned int N> T dot(const Vector<T, N> &l, const Vector<T
#include <iostream>
#include <array>
template <typename T, unsigned int N>
using Vector = std::array<T, N>;
template <typename T, unsigned int N>
T dot(const Vector<T, N> &l, const Vector<T, N> &r) {
T result{0};
for (auto i = 0; i < N; ++i) {
result += l[i] * r[i];
}
return result;
}
using Vector3f = Vector<float, 3>;
int main(int argc, const char * argv[]) {
Vector3f u{1.0f, 2.0f, 3.0f};
Vector3f v{6.0f, 5.0f, 4.0f};
std::cout << dot(u, v) << std::endl;
return 0;
}
以下是我得到的错误:
repro.cpp:24:18: error: no matching function for call to 'dot'
std::cout << dot(u, v) << std::endl;
^~~
repro.cpp:10:3: note: candidate template ignored: substitution failure [with T = float]: deduced non-type template
argument does not have the same type as the its corresponding template parameter
('unsigned long' vs 'unsigned int')
T dot(const Vector<T, N> &l, const Vector<T, N> &r) {
^
1 error generated.
repo.cpp:24:18:错误:调用“dot”时没有匹配函数
std::cout用std::size\u t
替换unsigned int
的所有实例。std::array
类模板声明为
template< class T, std::size_t N > struct array;
std::cout << dot<float, 3>(u, v) << std::endl;
template< class T, std::size_t N > struct array;
template <typename T, std::size_t N> // <--
using Vector = std::array<T, N>;
template <typename T, std::size_t N> // <--
T dot(const Vector<T, N> &l, const Vector<T, N> &r);