C++归并排序产生缓冲区溢出和未初始化内存的警告

Question

写了一个简单的归并排序，产生了警告C6386写入 "temp" 时缓冲区溢出和警告C6001使用未初始化的内存“*temp”。

void merge(int* arr, const int& left, const int& mid, const int& right)
{
    int i = left;
    int j = mid + 1;
    const int len = (right - left) + 1;
    int* temp = new int[len];
    int k = 0;
    while (i <= mid && j <= right)
        temp[k++] = arr[i] < arr[j] ? arr[i++] : arr[j++];
    while (i <= mid)
        temp[k++] = arr[i++];
    while (j <= right)
        temp[k++] = arr[j++];//缓冲区溢出？
    for (int i = 0; i < len; ++i)
        arr[left + i] = temp[i];//未初始化内存？
    delete[]temp;
}

void mergeSort(int* arr, const int& left, const int& right)
{
    if (left == right)
        return;
    int mid = (left + right) >> 1;
    mergeSort(arr, left, mid);
    mergeSort(arr, mid + 1, right);
    merge(arr, left, mid, right);
}

void MergeSort::sort(int* arr, const int& len)
{
    cout << "归并排序" << endl;
    mergeSort(arr, 0, len - 1);
}

找了半天没发现警告的原因，经过测试程序是能正常运行的。

Answer 1

溢出问题单点调试下，你看看right>arr长度的情况，修改下第一个循环：

void merge(int* arr, const int& left, const int& mid, const int& right)
{
    int i = left;
    int j = mid + 1;
    const int len = (right - left) + 1;
    int* temp = new int[len];
    int k = 0;
   while (i <= mid && j <= right && k < len)
    temp[k++] = arr[i] < arr[j] ? arr[i++] : arr[j++];
    while (i <= mid)
        temp[k++] = arr[i++];
    while (j <= right)
        temp[k++] = arr[j++];//缓冲区溢出？
    for (int i = 0; i < len; ++i)
        arr[left + i] = temp[i];//未初始化内存？
    delete[]temp;
}