1 #include 
     
       // for assert() 2 #include 
      
        // for std::initializer_list 3 #include 
       
         4   5 class IntArray 6 { 7 private: 8     int m_length; 9     int *m_data;10  11 public:12     IntArray() :13         m_length(0), m_data(nullptr)14     {15     }16  17     IntArray(int length) :18         m_length(length)19     {20         m_data = new int[length];21     }22  23     IntArray(const std::initializer_list
        
          &list): // allow IntArray to be initialized via list initialization24         IntArray(list.size()) // use delegating constructor to set up initial array25     {26         // Now initialize our array from the list27         printf("initializer_lis start!!!!\n");28         29         int count = 0;30         for (auto &element : list)31         {32             m_data[count] = element;33             ++count;34         }35     }36      IntArray(const IntArray &array)37     {38         m_length = array.m_length;39         m_data = new int[m_length];40         41         int i = 0;42         for (; i < m_length; i++)43         {44             m_data[i] = array.m_data[i];45         }46     }47         48     ~IntArray()49     {50         delete[] m_data;51         // we don't need to set m_data to null or m_length to 0 here, since the object will be destroyed immediately after this function anyway52     }53  54     int& operator[](int index)55     {56         assert(index >= 0 && index < m_length);57         return m_data[index];58     }59     void operator=(const std::initializer_list
         
           &list)60     {61         m_length = list.size();62         m_data = new int[m_length];63         int count = 0;64         for (auto &element : list)65         {66             m_data[count] = element;67             ++count;68         }69 70     }71     72     void operator=(const IntArray &array)73     {74         m_length = array.m_length;75         m_data = new int[m_length];76         77         int i = 0;78         for (; i < m_length; i++)79         {80             m_data[i] = array.m_data[i];81         }82 83 84     }85     int getLength() { return m_length; }86 };