如何使用的shared_ptr或建议另一种方法（的unique_ptr）

-1

UPD：所以解决方案的要点是：如果拷贝构造函数存在，它可以防止移动的构造被称为std::move。问题解决了。
我试着写一个“线程安全的堆叠”因此，以讲师的要求：如何使用的shared_ptr或建议另一种方法（的unique_ptr）

应该存储类型本身。
对于原始类型它应该接收/通过复制（在C照常）返回
对于类型它不应调用冗余拷贝构造上收到/回报。使用shared_ptr来实现这一点。

而且我不能让3号工作。

更具体地说：我不知道如何将shared_ptr传递给这样设计的类。此外，我几乎可以肯定，我已经写了这个类本身在语法上是错误的。

#ifndef SAFE_QUEUE 
#define SAFE_QUEUE 

#include <condition_variable> 
#include <thread> 
#include <stdlib.h> 
#include <queue> 
#include <mutex> 
#include <chrono> 

template<typename T> 
class SafeQueue { 

public: 
    SafeQueue() { 
     printf("CONSTRUCTOR\n"); 
    } 

    ~SafeQueue() { 
     printf("DESTRUCTOR\n"); 
    } 

    void push(T data) { 
     std::unique_lock<std::mutex> lock(_m); 
     _queue.push(data); 
     printf("Pushed %d\n", data); 
     _cv.notify_one(); 
    } 

    void push(std::shared_ptr<T> data) { 
     std::unique_lock<std::mutex> lock(_m); 
     _queue.push(*data); 
     _cv.notify_one(); 
    } 

    bool pop_top(T &outEl) { 
     std::unique_lock<std::mutex> lock(_m); 
     while (1) { 
      bool a; 
      if (a = this->_cv.wait_for(lock, std::chrono::milliseconds(1000), 
             [this]() -> bool { return !(this->_queue.empty()); })) { 
       printf(" \n\n//Wait for returned %d \n", a); 
       if (!(_queue.empty())) { 
        outEl = _queue.front(); 
        _queue.pop(); 
        return true; 
       } else { 
        continue; 
       } 
      } else { 
       printf(" \n\n//Wait for returned %d \n", a); 
       printf("Queue is empty\n"); 
       return false; 
      } 
     } 
    } 

    std::shared_ptr<T> pop_top() { 
     std::unique_lock<std::mutex> lock(_m); 
     while (1) { 
      bool a; 
      if (a = this->_cv.wait_for(lock, std::chrono::milliseconds(1000), 
             [this]() -> bool { return !(this->_queue.empty()); })) { 
       printf(" \n\n//Wait for returned %d \n", a); 
       if (!(_queue.empty())) { 
        std::shared_ptr<T> cur = std::make_shared<T>(_queue.front()); 
        _queue.pop(); 

        return cur; 
       } else { 
        continue; 
       } 
      } else { 
       printf(" \n\n//Wait for returned %d \n", a); 
       printf("Queue is empty\n"); 
       return nullptr; 
      } 
     } 
    } 

private: 
    std::queue<T> _queue; 
    std::condition_variable _cv; 
    std::mutex _m; 
}; 


#endif

主：

#include <iostream> 
#include "safeQueue.h" 
#include <vector> 


void forEven(SafeQueue<int> *sq, int numThread){ 
    // for(int i=0;i<3;i++) 
    // sq->push(i+numThread); 
    // sq->push(1); 
    // for(int i=0;i<2;i++) 
    //sq->push(numThread); 
    int z; 
    if(sq->pop_top(z)) 
    printf("even popped:%d\n", z); 
    sq->push(numThread); 
    printf("even pushed:%d\n", numThread); 
} 

class myclass{ 
public: 
    int val; 
    myclass(myclass &obj){ 
     printf("copy constructor"); 
    } 
    myclass(int val):val(val){ 
     printf("constructor"); 
    } 
    ~myclass(){ 
     printf("destructor"); 
    } 
}; 

void forOdd(SafeQueue<int> *sq, int numThread){ 
    int z; 
    if(sq->pop_top(z)) 
    printf("odd popped:%d\n", z); 
    if(sq->pop_top(z)) 
    printf("odd popped:%d\n", z); 


    for(int i=0;i<2;i++) { 
     sq->push(i + numThread); 
     printf("odd pushed:%d\n", i + numThread); 
    } 

    if(sq->pop_top(z)) 
    printf("odd popped:%d\n", z); 
    if(sq->pop_top(z)) 

printf("odd popped:%d\n", z); 
} 

void forEven_class(SafeQueue<myclass> *sq, myclass &el){ 
    // for(int i=0;i<3;i++) 
    // sq->push(i+numThread); 
    // sq->push(1); 
    // for(int i=0;i<2;i++) 
    //sq->push(numThread); 
    std::shared_ptr<myclass> z = std::move(sq->pop_top()); 
    if(z) 
     printf("even popped:%d\n", z->val); 
    sq->push(std::make_shared<myclass>(el)); 
    printf("even pushed:%d\n", el.val); 
} 

void forOdd_class(SafeQueue<myclass> *sq, myclass &el){ 
    std::shared_ptr<myclass> z = std::move(sq->pop_top()); 
    if(z) 
    printf("odd popped:%d\n", z->val); 
    z = std::move(sq->pop_top()); 
    if(z) 
     printf("odd popped:%d\n", z->val); 


    for(int i=0;i<2;i++) { 
     sq->push(std::make_shared<myclass>(i + el.val)); 
     printf("odd pushed:%d\n", i + el.val); 
    } 

    z = std::move(sq->pop_top()); 
    if(z) 
     printf("odd popped:%d\n", z->val); 
    z = std::move(sq->pop_top()); 
    if(z) 
     printf("odd popped:%d\n", z->val); 
} 

int main(){ 
    SafeQueue<int> sq; 

    SafeQueue<myclass> sq_c; 

    std::vector<std::thread> v_t; 

    for(int i=0;i<5;i++){ 
     if(i%2) 
      v_t.push_back(move(std::thread(forOdd,&sq,i+1))); 
     else 
      v_t.push_back(move(std::thread(forEven,&sq,i+1))); 
    } 

    for(int i=0;i<5;i++){ 
     v_t[i].join(); 
    } 

    std::cout << "class test" <<std::endl; 
    for(int i=0;i<5;i++){ 
     if(i%2) 
      v_t.push_back(move(std::thread(forOdd_class,&sq_c,std::move(myclass(i+1))))); 
     else 
      v_t.push_back(move(std::thread(forEven_class,&sq_c,std::move(myclass(i+1))))); 
    } 

    for(int i=0;i<5;i++){ 
     v_t[i].join(); 
    } 

    // std::thread t1(forThreads,&sq,1); 
    // std::thread t2(forThreads,&sq,2); 
    // std::thread t3(forThreads,&sq,2); 
    // 
    // t1.join(); 
    // t2.join(); 
    // t3.join(); 


    return 0; 
}

我不能因为enourmous错误forEven_class（）和forOdd_class（）工作：

如果我离开只是注释掉定义forEven/Odd_class函数我得到：

error: no matching function for call to ‘myclass::myclass(const myclass&)’

如此看来共享PTR试图调用拷贝构造函数

如果我取消一切，我得到了全：

In file included from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/mutex:42:0, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/condition_variable:39, 
       from /gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/safeQueue.h:9, 
       from /gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:2: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/functional: In instantiation of ‘struct std::_Bind_simple<void (*(SafeQueue<myclass>*, myclass))(SafeQueue<myclass>*, myclass&)>’: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/thread:137:47: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = void (&)(SafeQueue<myclass>*, myclass&); _Args = {SafeQueue<myclass>*, myclass}]’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:116:86: required from here 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/functional:1665:61: error: no type named ‘type’ in ‘class std::result_of<void (*(SafeQueue<myclass>*, myclass))(SafeQueue<myclass>*, myclass&)>’ 
     typedef typename result_of<_Callable(_Args...)>::type result_type; 
                  ^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/functional:1695:9: error: no type named ‘type’ in ‘class std::result_of<void (*(SafeQueue<myclass>*, myclass))(SafeQueue<myclass>*, myclass&)>’ 
     _M_invoke(_Index_tuple<_Indices...>) 
     ^
In file included from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/mutex:38:0, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/condition_variable:39, 
       from /gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/safeQueue.h:9, 
       from /gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:2: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple: In instantiation of ‘struct std::_Head_base<2ul, myclass, false>’: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:231:12: recursively required from ‘struct std::_Tuple_impl<1ul, SafeQueue<myclass>*, myclass>’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:231:12: required from ‘struct std::_Tuple_impl<0ul, void (*)(SafeQueue<myclass>*, myclass&), SafeQueue<myclass>*, myclass>’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:390:11: required from ‘class std::tuple<void (*)(SafeQueue<myclass>*, myclass&), SafeQueue<myclass>*, myclass>’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/functional:1703:39: required from ‘struct std::_Bind_simple<void (*(SafeQueue<myclass>*, myclass))(SafeQueue<myclass>*, myclass&)>’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/thread:137:47: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = void (&)(SafeQueue<myclass>*, myclass&); _Args = {SafeQueue<myclass>*, myclass}]’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:116:86: required from here 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:137:17: error: ‘constexpr std::_Head_base<_Idx, _Head, false>::_Head_base(const std::_Head_base<_Idx, _Head, false>&) [with long unsigned int _Idx = 2ul; _Head = myclass]’ declared to take const reference, but implicit declaration would take non-const 
     constexpr _Head_base(const _Head_base&) = default; 
       ^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple: In instantiation of ‘constexpr std::_Head_base<_Idx, _Head, false>::_Head_base(_UHead&&) [with _UHead = myclass; long unsigned int _Idx = 2ul; _Head = myclass]’: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:273:42: required from ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(std::_Tuple_impl<_Idx, _Head, _Tail ...>&&) [with long unsigned int _Idx = 2ul; _Head = myclass; _Tail = {}]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/type_traits:900:43: required by substitution of ‘template<class _Tp, class _Arg, class> static std::true_type std::__do_is_direct_constructible_impl::__test(int) [with _Tp = std::_Tuple_impl<2ul, myclass>; _Arg = std::_Tuple_impl<2ul, myclass>&&; <template-parameter-1-3> = <missing>]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/type_traits:912:43: required from ‘struct std::__is_direct_constructible_impl<std::_Tuple_impl<2ul, myclass>, std::_Tuple_impl<2ul, myclass>&&>’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/type_traits:134:12: required from ‘struct std::__and_<std::is_destructible<std::_Tuple_impl<2ul, myclass> >, std::__is_direct_constructible_impl<std::_Tuple_impl<2ul, myclass>, std::_Tuple_impl<2ul, myclass>&&> >’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/type_traits:916:12: required from ‘struct std::__is_direct_constructible_new_safe<std::_Tuple_impl<2ul, myclass>, std::_Tuple_impl<2ul, myclass>&&>’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/type_traits:994:12: [ skipping 21 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ] 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/type_traits:1175:12: required from ‘struct std::is_nothrow_move_constructible<std::_Tuple_impl<1ul, SafeQueue<myclass>*, myclass> >’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/type_traits:134:12: required from ‘struct std::__and_<std::is_nothrow_move_constructible<void (*)(SafeQueue<myclass>*, myclass&)>, std::is_nothrow_move_constructible<std::_Tuple_impl<1ul, SafeQueue<myclass>*, myclass> > >’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:269:7: required from ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(std::_Tuple_impl<_Idx, _Head, _Tail ...>&&) [with long unsigned int _Idx = 0ul; _Head = void (*)(SafeQueue<myclass>*, myclass&); _Tail = {SafeQueue<myclass>*, myclass}]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/functional:1727:41: required from ‘typename std::_Bind_simple_helper<_Func, _BoundArgs>::__type std::__bind_simple(_Callable&&, _Args&& ...) [with _Callable = void (&)(SafeQueue<myclass>*, myclass&); _Args = {SafeQueue<myclass>*, myclass}; typename std::_Bind_simple_helper<_Func, _BoundArgs>::__type = std::_Bind_simple<void (*(SafeQueue<myclass>*, myclass))(SafeQueue<myclass>*, myclass&)>]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/thread:137:47: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = void (&)(SafeQueue<myclass>*, myclass&); _Args = {SafeQueue<myclass>*, myclass}]’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:116:86: required from here 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:142:42: error: no matching function for call to ‘myclass::myclass(myclass)’ 
    : _M_head_impl(std::forward<_UHead>(__h)) { } 
             ^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:142:42: note: candidates are: 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:32:5: note: myclass::myclass(int) 
    myclass(int val):val(val){ 
    ^
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:32:5: note: no known conversion for argument 1 from ‘myclass’ to ‘int’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:29:5: note: myclass::myclass(myclass&) 
    myclass(myclass &obj){ 
    ^
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:29:5: note: no known conversion for argument 1 from ‘myclass’ to ‘myclass&’ 
In file included from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/mutex:38:0, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/condition_variable:39, 
       from /gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/safeQueue.h:9, 
       from /gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:2: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple: In instantiation of ‘constexpr std::_Head_base<_Idx, _Head, false>::_Head_base(const _Head&) [with long unsigned int _Idx = 2ul; _Head = myclass]’: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:257:44: recursively required from ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const _Head&, const _Tail& ...) [with long unsigned int _Idx = 1ul; _Head = SafeQueue<myclass>*; _Tail = {myclass}]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:257:44: required from ‘constexpr std::_Tuple_impl<_Idx, _Head, _Tail ...>::_Tuple_impl(const _Head&, const _Tail& ...) [with long unsigned int _Idx = 0ul; _Head = void (*)(SafeQueue<myclass>*, myclass&); _Tail = {SafeQueue<myclass>*, myclass}]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:400:33: required from ‘constexpr std::tuple< <template-parameter-1-1> >::tuple(const _Elements& ...) [with _Elements = {void (*)(SafeQueue<myclass>*, myclass&), SafeQueue<myclass>*, myclass}]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/functional:1678:74: required from ‘std::_Bind_simple<_Callable(_Args ...)>::_Bind_simple(_Callable&&, _Args2&& ...) [with _Args2 = {SafeQueue<myclass>*, myclass}; <template-parameter-2-2> = void; _Callable = void (*)(SafeQueue<myclass>*, myclass&); _Args = {SafeQueue<myclass>*, myclass}]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/functional:1727:41: required from ‘typename std::_Bind_simple_helper<_Func, _BoundArgs>::__type std::__bind_simple(_Callable&&, _Args&& ...) [with _Callable = void (&)(SafeQueue<myclass>*, myclass&); _Args = {SafeQueue<myclass>*, myclass}; typename std::_Bind_simple_helper<_Func, _BoundArgs>::__type = std::_Bind_simple<void (*(SafeQueue<myclass>*, myclass))(SafeQueue<myclass>*, myclass&)>]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/thread:137:47: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = void (&)(SafeQueue<myclass>*, myclass&); _Args = {SafeQueue<myclass>*, myclass}]’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:116:86: required from here 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:135:25: error: no matching function for call to ‘myclass::myclass(const myclass&)’ 
     : _M_head_impl(__h) { } 
         ^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/tuple:135:25: note: candidates are: 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:32:5: note: myclass::myclass(int) 
    myclass(int val):val(val){ 
    ^
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:32:5: note: no known conversion for argument 1 from ‘const myclass’ to ‘int’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:29:5: note: myclass::myclass(myclass&) 
    myclass(myclass &obj){ 
    ^
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:29:5: note: no known conversion for argument 1 from ‘const myclass’ to ‘myclass&’ 
In file included from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/x86_64-redhat-linux/bits/c++allocator.h:33:0, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/allocator.h:46, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/string:41, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/locale_classes.h:40, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/ios_base.h:41, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/ios:42, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/ostream:38, 
       from /opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/iostream:39, 
       from /gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:1: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/ext/new_allocator.h: In instantiation of ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...) [with _Up = myclass; _Args = {const myclass&}; _Tp = myclass]’: 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_deque.h:1403:6: required from ‘void std::deque<_Tp, _Alloc>::push_back(const value_type&) [with _Tp = myclass; _Alloc = std::allocator<myclass>; std::deque<_Tp, _Alloc>::value_type = myclass]’ 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/bits/stl_queue.h:216:9: required from ‘void std::queue<_Tp, _Sequence>::push(const value_type&) [with _Tp = myclass; _Sequence = std::deque<myclass, std::allocator<myclass> >; std::queue<_Tp, _Sequence>::value_type = myclass]’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/safeQueue.h:37:9: required from ‘void SafeQueue<T>::push(std::shared_ptr<_Tp1>) [with T = myclass]’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:69:43: required from here 
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/ext/new_allocator.h:120:4: error: no matching function for call to ‘myclass::myclass(const myclass&)’ 
    { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } 
    ^
/opt/rh/devtoolset-3/root/usr/include/c++/4.9.2/ext/new_allocator.h:120:4: note: candidates are: 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:32:5: note: myclass::myclass(int) 
    myclass(int val):val(val){ 
    ^
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:32:5: note: no known conversion for argument 1 from ‘const myclass’ to ‘int’ 
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:29:5: note: myclass::myclass(myclass&) 
    myclass(myclass &obj){ 
    ^
/gpfs/home/ichernovalov/Sharamet/Threads 1 2 5 6/5 safeQueue/main.cpp:29:5: note: no known conversion for argument 1 from ‘const myclass’ to ‘myclass&’

所以我不知道如何使用的shared_ptr的。（特别是将它传递给线程）我可能让讲师错了。那么你会推荐使用什么：unque_ptr或什么？

来源

2017-06-16 Rules

_“无法工作”_是一个太模糊的问题描述。发布一个[MCVE]，请重现您的问题。 –

“我不能让x工作”并不是一个学生学习编码的充分的错误报告。您需要告诉我们您的预期和实际得到的结果，作为最低限度。 – Rook

请阅读[MCVE] –

删除不必要的构造函数和析构函数，并更改Even_class和forOdd_class的函数，您的代码将为compile again。
为什么要移除构造函数？因为编译器有规则如何生成默认的构造函数。在你的情况下，你想要移动构造函数生成，但通过定义复制构造函数和析构函数，你阻止编译器这样做。您的选项是：

正确定义所有的构造函数，包括移动构造函数
删除拷贝构造函数和析构函数，我建议，因为他们没有做任何事情execpt首张输出
请示编译器生成默认的移动构造函数myclass(myclass &&obj) = default

看到这个在automatic generation of move operations 我想要那些调试消息，那么你必须正确定义这些构造函数。包括除调试消息以外的任务。

关于对于Even_class函数的更改，您不能通过引用使用myclass，因为它不是左值。有关此google rvalue参考的更多信息。

来源

2017-06-16 21:35:53

如何使用的shared_ptr或建议另一种方法（的unique_ptr）

回答

相关问题