C++: the function collapses at the 4th element of the array - c++

Question

Could you have a look at what I've faced: http://sdrv.ms/WgafvN
And another screenshot: http://sdrv.ms/UZIp6H
The text of my function is:
bool print_all_points(POINT** pointer)
{
if (pointer == NULL||is_array_empty(pointer))
{
cout << "The array of points is empty." << endl << endl;
return false;
}
else
{
int n = _msize(pointer)/sizeof(pointer[0]);
cout << "The list of points: " << endl<< endl;
cout << "id (x, y)" << endl;
cout << "----------" << endl;
for (int i = 0; i < n; i++)
{
cout << (*pointer[i]).id << " (" << (*pointer[i]).x << ", " << (*pointer[i]).y << ")" << endl;
}
}
return true;
}
This function is expected to print out all the points in an array. My problem is that it perfectly prints the array of 3 points rather than that of 4 points. At the 4th point it bites the dust.
I can't catch what the trouble is.
From the picture it is visible that:
1. All 4 elements of the array are present.
2. It is correctly determined that there 4 of them.
What is the problem?
Could you give me a kick here?
ADDED LATER.
The function which calls this:
POINT** new_point(POINT** pointer, int occup)
{
char x;
char y;
system("cls");
cout << "INPUT A NEW POINT" << endl << endl;
cout << "Input x: ";
cin >> x;
cout << "Input y: ";
cin >> y;
size_t m;
if (pointer != NULL)
{
m = _msize(pointer);
}
POINT * tmp_point = new POINT();
(*tmp_point).id = occup;
(*tmp_point).x = x-48;
(*tmp_point).y = y-48;
POINT** pn = new POINT * [occup];
int necessary_memory = occup * 4; // ???? 4 is the size of a pointer.
if (occup !=1)
{
memcpy(pn, pointer, necessary_memory);
}
POINT ** tmp = new POINT * [occup];
pn[occup - 1] = tmp_point;
memcpy(tmp, pn, occup * sizeof(POINT));
delete[] pn;
pn = tmp;
size_t n = _msize(pn);
cout << endl;
print_all_points(pn);
return pn;
}

Answer 1

several problems:
not copying enough data in 64-bit
int necessary_memory = occup * 4;
should be
int necessary_memory = occup * sizeof(POINT*);
copying too much data
memcpy(tmp, pn, occup * sizeof(POINT));
should be:
memcpy(tmp, pn, occup * sizeof(POINT*));
Someone else can chime in, but I am not sure _msize should be used on memory allocated by new. Is that right? http://msdn.microsoft.com/en-us/library/z2s077bc(v=vs.80).aspx
fucntion in the title should be function
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