你能投射一个向量吗<int64>到一个向量<uint8>

Question

In C++ what is the correct way to cast a vector of int64_t to uint8_t ?

I understand I could to this:

std::vector<int64_t> int64Vec;
std::vector<uint8_t> uint8Vec(int64Vec.begin(), int64Vec.end());

But I think creates an unnecessary copy. Is it possible to cast the vector?

The reason why is that uint8vec is passed to a function which expects a uint8_t vector.

Answer 1

Is it possible to cast the vector?

No.

The reason why is that uint8vec is passed to a function which expects a uint8_t vector.

What should be fixed is that function. If the function would accept iterators instead (that when dereferenced yield a type that can be converted to uint8_t ) there would be no issue:

template <typename IT>
void function( IT begin, IT end);

Perhaps add sanity checks for the type IT to get readable error messages in case IT does not dereference to a type that can be converted to uint8_t .