질문입니다

안녕하세요

// 9_12.cpp : This file contains the 'main' function. Program execution begins and ends there.

//



#include <iostream>

#include <cassert>

#include <initializer_list>



using namespace std;



class IntArray

{

private:

    unsigned m_length = 0;

    int* m_data = nullptr;



public:

    IntArray(unsigned length = 0)

        : m_length(length)

    {

        m_data = new int[length];

    }



    IntArray(const std::initializer_list<int>& list)

        : IntArray(list.size())

    {

        cout << "list.size() In constructor " << list.size() << endl;

        int count = 0;

        for (auto& element : list)

        {

            m_data[count] = element;

            ++count;

        }



        //for (unsigned count = 0; count < list.size(); ++count)

        //  m_data[count] = list[count];    // error



    }

    ~IntArray()

    {

        delete[] this->m_data;

    }



    IntArray& operator=(const std::initializer_list<int>& list)

    {

        cout << "assignment operator" << endl;

        cout << "list.size() In assignment operator " << list.size() << endl;



        delete[] m_data;

        int length = list.size();



        m_data = new int[length];



        int count = 0;

        for (auto& element : list)

        {

            m_data[count] = element;

            ++count;

        }



        return *this;

    }



    friend std::ostream& operator << (std::ostream& out, const IntArray& arr)

    {

        for (unsigned i = 0; i < arr.m_length; ++i)

            out << arr.m_data[i] << " ";

        out << endl;

        return out;

    }

};

int main()

{

    int my_arr1[5] = { 1,2, 3,4,5 };

    int* my_arr2 = new int[5]{ 1,2,3,4,5 };



    auto il = { 10, 20, 30 };



    IntArray int_array { 1, 2, 3, 4, 5 };

    cout << int_array << endl;

    int_array = {7, 2, 3, 2, 1, 6, 5};

    cout << int_array << endl;

    



    return 0;

}

이 코드에서 operator = 에 사이즈 7로 잘들어가는데 

cout << int_array<<endl; 마지막줄을 실행시킬때

5개만 나오는데 왜그런지 모르겠습니다 ㅜㅜ

그리고 initializer_list 를 왜사용해랴하는지도 정확하게 알지못하겠습니다 ㅜ