moveable items in vector, C++ (vc++)

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//Microsoft (R) C/C++ Optimizing Compiler Version 19.00.23506 for x64

#include <iostream>
#include <string>
#include <fstream>
#include <type_traits>
#include <vector>

struct A // moveable, but non_copyable
{
    A() = default ;
    explicit A( const std::string& path ) : file(path) {}
    explicit A( std::ofstream&& stm ) : file( std::move(stm) ) {}

bool can_write() const { return file.is_open() && file ; }

std::ofstream file ;
    // copy constructor and copy assignment operator are implicitly deleted
};

int main()
{
    std::cout << std::boolalpha
              << "copy constructible? " << std::is_copy_constructible<A>::value << '\n'
              << "copy assignable? " << std::is_copy_assignable<A>::value << '\n'
              << "move constructible? " << std::is_move_constructible<A>::value << '\n'
              << "move assignable? " << std::is_move_assignable<A>::value << "\n\n" ;

std::vector<A> vec ;
    vec.emplace_back( "123.txt" ) ;
    std::cout << "size: " << vec.size() << " capacity: " << vec.capacity() << '\n' ;

vec.emplace_back( "456.txt" ) ;
    std::cout << "size: " << vec.size() << " capacity: " << vec.capacity() << '\n' ;

vec.resize(7) ;
    std::cout << "size: " << vec.size() << " capacity: " << vec.capacity() << '\n' ;

vec.emplace_back( std::ofstream( "789.txt" ) ) ;
    std::cout << "size: " << vec.size() << " capacity: " << vec.capacity() << '\n' ;

{
        A a( "abcd.txt" ) ;
        vec.push_back( std::move(a) ) ; // don't use the moved from a after this
        std::cout << "size: " << vec.size() << " capacity: " << vec.capacity() << '\n' ;
    }

vec.erase( vec.begin()+3, vec.begin()+6 ) ;
    std::cout << "size: " << vec.size() << " capacity: " << vec.capacity() << "\n\n" ;

for( const A& a : vec ) std::cout << a.can_write() << ' ' ;
    std::cout << '\n' ;
}

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Compilation time: 2,04 sec, absolute running time: 0,32 sec, absolute service time: 2,38 sec