error when use std::thread in Class

I tried to use std::thread in Visual Studio 2013. It works all right like this.

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <chrono>    // std::chrono::seconds
#include <iostream>  // std::cout
#include <thread>    // std::thread, std::this_thread::sleep_for
#include <vector>
void thread_task(int n) {
    std::this_thread::sleep_for(std::chrono::seconds(n));
    std::cout << "hello thread "
        << std::this_thread::get_id()
        << " paused " << n << " seconds" << std::endl;
}
int _tmain(int argc, _TCHAR* argv[])
{
    std::vector<std::thread> threads;
    std::cout << "Spawning 5 threads...\n";
    for (int i = 0; i < 5; i++) {
        threads.emplace_back( std::thread(thread_task, i + 1));
    }
    std::cout << "Done spawning threads! Now wait for them to join\n";
    for (auto& t : threads) {
        t.join();
    }
    std::cout << "All threads joined.\n";
    return 0;
}

but when I tried to make thread in a Class, I met some compiling errors.

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <chrono>    // std::chrono::seconds
#include <iostream>  // std::cout
#include <thread>    // std::thread, std::this_thread::sleep_for
#include <vector>
class MyClass
{
public:
    MyClass();
    void thread_task(int n);
    ~MyClass();
private:
};
MyClass::MyClass()
{
    std::vector<std::thread> threads;
    std::cout << "Spawning 5 threads...\n";
    for (int i = 0; i < 5; i++) {
        threads.emplace_back(std::thread(&MyClass::thread_task, i + 1));
    }
    std::cout << "Done spawning threads! Now wait for them to join\n";
    for (auto& t : threads) {
        t.join();
    }
    std::cout << "All threads joined.\n";
}
void MyClass::thread_task(int n) {
    std::this_thread::sleep_for(std::chrono::seconds(n));
    std::cout << "hello thread "
        << std::this_thread::get_id()
        << " paused " << n << " seconds" << std::endl;
}
MyClass::~MyClass(){}
int _tmain(int argc, _TCHAR* argv[])
{   
    MyClass test();
    return 0;
}

The error messages are copied below.

1>c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(1149): error C2064: term does not evaluate to a function taking 1 arguments
1>          class does not define an 'operator()' or a user defined conversion operator to a pointer-to-function or reference-to-function that takes appropriate number of arguments
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(1137) : see reference to function template instantiation 'void std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>::_Do_call<,0>(std::tuple<>,std::_Arg_idx<0>)' being compiled
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(1137) : see reference to function template instantiation 'void std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>::_Do_call<,0>(std::tuple<>,std::_Arg_idx<0>)' being compiled
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\thr\xthread(195) : see reference to function template instantiation 'void std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>::operator ()<>(void)' being compiled
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\thr\xthread(195) : see reference to function template instantiation 'void std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>::operator ()<>(void)' being compiled
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\thr\xthread(192) : while compiling class template member function 'unsigned int std::_LaunchPad<_Target>::_Run(std::_LaunchPad<_Target> *)'
1>          with
1>          [
1>              _Target=std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\thr\xthread(187) : see reference to function template instantiation 'unsigned int std::_LaunchPad<_Target>::_Run(std::_LaunchPad<_Target> *)' being compiled
1>          with
1>          [
1>              _Target=std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\thr\xthread(205) : see reference to class template instantiation 'std::_LaunchPad<_Target>' being compiled
1>          with
1>          [
1>              _Target=std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\thread(49) : see reference to function template instantiation 'void std::_Launch<std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>>(_Thrd_t *,_Target &&)' being compiled
1>          with
1>          [
1>              _Target=std::_Bind<true,void,std::_Pmf_wrap<void (__thiscall MyClass::* )(int),void,MyClass,int>,int>
1>          ]
1>          d:\projects\consoleapplication2\consoleapplication2\consoleapplication2.cpp(29) : see reference to function template instantiation 'std::thread::thread<void(__thiscall MyClass::* )(int),int>(_Fn &&,int &&)' being compiled
1>          with
1>          [
1>              _Fn=void (__thiscall MyClass::* )(int)
1>          ]
1>

What cause the problem? Can anyone help me? Thanks a lot.