Copying non null-terminated unsigned char array to std::string

std::string has a constructor that takes a pair of iterators and unsigned char can be converted (in an implementation defined manner) to char so this works. There is no need for a reinterpret_cast.

unsigned char u_array[4] = { 'a', 's', 'd', 'f' };

#include <string>
#include <iostream>
#include <ostream>

int main()
{
    std::string str( u_array, u_array + sizeof u_array / sizeof u_array[0] );
    std::cout << str << std::endl;
    return 0;
}

Of course an "array size" template function is more robust than the sizeof calculation.

Well, apparently std::string has a constructor that could be used in this case:

std::string str(reinterpret_cast<char*>(u_array), 4);