将一个数组分配给堆上的另一个数组 C++

Question

T is = to char
counts_ is an array of integers stored on the heap
values_ is an array of arrays on the heap

Problem arrives in the if statement, when I try to delete tmpe I get an error. If I comment the delete statement out, the code runs but it just keeps pointing all of my pointers in values_ to the same array. The idea of the code is to create a new array containing the values of one of the selected values_ arrays and then add one extra value to it. Then re-assign it back to the spot in the values_ array that I took it from. The tmpe array is holding the correct values up to the point that I attempt to delete the pointer to it. I get a Aborted (core dumped) error upon running my entire program.

if (initialized(n) == true)
{   
    T *tmpe = new T[counts_[n] + 1];
    for (size_type i = 0; i < counts_[n]; i++)
    {
        tmpe[i] = values_[n][i];
    }
    tmpe[counts_[n]] = val;
    delete [] values_[n];
    values_[n] = tmpe;
    delete [] tmpe;
    counts_[n]++;
}
else
{
    T *tmpd = new T[counts_[n] + 1];
    tmpd[counts_[n]] = val;
    delete [] values_[n];
    values_[n] = tmpd;
    delete [] tmpd;
    counts_[n]++;
}

Answer 1

The issue is that you keep a pointer to tmpe but promptly deallocate the memory:

values_[n] = tmpe;
delete [] tmpe;

When the next iteration tries to access and/or delete values_[n] , it's a dangling pointer.

The same goes for tmpd .

If you used std::vector , you wouldn't have to worry about problems like this.

Answer 2

You don't need to delete tmpd after you reassign values_ to point to it. As soon as you reassign it, the memory is freed. What's happening is that you're trying to free something that doesn't exist.