使用复制构造函数 C++ 时出现分段错误

Question

一切似乎都可以正常复制，但是当我调用 array2.print() 时，它显示分段错误。我做错了什么？

#include <iostream>
#include <initializer_list>


template <typename T>
class DynamicArray
{
private:
    const int GROWTH_FACTOR = 2;
    const int INITIAL_CAPACITY = 5;

    T *m_array;
    int m_capacity; // Capacity of the array
    int m_size; // Number of added elements

public:
    DynamicArray(std::initializer_list<T> elements)
        : m_size(elements.size()) 
        , m_capacity(elements.size() * 2)
    {
        m_array = new T[m_capacity];
        std::copy(elements.begin(), elements.end(), m_array);
    }

    DynamicArray()
        : m_size(0)
        , m_capacity(INITIAL_CAPACITY)
    {
        m_array = new T[m_capacity];
    }

    ~DynamicArray()
    {
        delete[] m_array;
    }

    DynamicArray(const DynamicArray& other)
        : GROWTH_FACTOR(other.GROWTH_FACTOR)
        , INITIAL_CAPACITY(other.INITIAL_CAPACITY)
        , m_capacity(other.m_capacity)
        , m_size(other.m_size)
    {
        T *m_array = new T[m_capacity];
        std::copy(other.m_array, other.m_array + m_size, m_array);
    }

    int size()
    {
        return m_size;
    }

    int capacity()
    {
        return m_capacity;
    }
    
    void resize()
    {
        int new_capacity = m_capacity *  GROWTH_FACTOR;
        m_capacity = new_capacity;
        T *temp = new T[new_capacity];
        std::copy(m_array, m_array + m_capacity, temp);
        delete[] m_array;
        m_array = temp;
    }

    void deleteAt(int pos) 
    {
        for (int i = pos; i < m_size - 1; i++)
        {
            (*this)[i] = (*this)[i + 1];
        }

        m_size--;
    }

    void insertAt(T value, int pos)
    {
        if (m_capacity == m_size)
        {
            resize();
        }

        for (int i = m_size - 1; i >= pos; i--)
        {
            (*this)[i + 1] = (*this)[i];
        }

        m_size++;
        (*this)[pos] = value;
    }

    void append(T value)
    {
        insertAt(value, m_size);
    }

    void print() {
        for (int i = 0; i < m_size; i++)
        {
            std::cout << (*this)[i] << ", ";
        }
        std::cout << std::endl;
    }

    T& operator[](int index)
    {
        if (index < 0 || index > m_size - 1)
        {
            throw std::invalid_argument("Index out of range!");
        }

        return m_array[index];
    }
    

};

int main()
{
    DynamicArray<int> array = { 1, 2, 3, 4 };
    DynamicArray<int> array2 = array;
    array2.print(); 
    return 0;
}

Answer 1

错误在这里

T *m_array = new T[m_capacity];

应该是

m_array = new T[m_capacity];

通过声明一个名为 m_array 的新变量，您隐藏了要分配给的 class 成员变量。这个的技术名称是 shadowing，一个好的编译器会警告你这个。

Answer 2

您在 cctor 中重新声明 m_array，这会隐藏 class 成员。

使用复制构造函数 C++ 时出现分段错误

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