Classes and Dynamic Memory

Question

I'm a little confused trying to understand what is happening here:

#include <iostream>

using namespace std;

class Point
{
  int x, y;
public:
  Point(): x(0), y(0) {}
  int getX() {return x;}
  int getY() {return y;}
};

int main(int argc, char const *argv[])
{
  Point *a = new Point[2];
  Point *b = a;

  for (int i = 0; i < 5; i++, a++)
    cout << a->getX() << "," << a->getY() << endl;

  delete[] b;

  return 0;
}

Output:

0,0
0,0
0,0
1041,0
825503793,667692

This is just an experiment, I looked at this when I was practicing with classes and dynamic memory. Why the output look like this, what is happening behind?

I'm sure than the 2 first Point will be initialized with the Point() constructor, so why the third is also 0,0? And why the other 2 have that random numbers, where are that objects allocated? Are there just random memory / uninitialized memory of Point type?

Accessing anything outside of the bounds of the array is undefined behavior. Anything goes there, no guarantees exist — UnholySheep, Oct 29 '16 at 19:47
As correctly noted, you should find more about this: http://stackoverflow.com/documentation/c%2b%2b/1812/undefined-behavior#t=201610291949243204604, before write more code. — Giorgi Moniava, Oct 29 '16 at 19:49
Btw, this is essentially the [same question you asked an hour ago](http://stackoverflow.com/questions/40321992/moving-pointer-with-dynamic-memory-c). Why are you so keen on experimenting with UB? — UnholySheep, Oct 29 '16 at 19:52
@UnholySheep Because obviously the guy didn't grasp the concept — Giorgi Moniava, Oct 29 '16 at 19:59
This is so undefined, that on my machine the output is 0,0 0,0 0,0 0,0 -1,-1 — Maxim Chetrusca, Oct 29 '16 at 20:01

Classes and Dynamic Memory

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