double *d = new double[N]

[NoobMathe]

#include <iostream>

using namespace std;

int main() {

  cout << "program started..." << endl;


  const int N = 1e6;

  for (int i = 0; i < N; ++i) {
    double *d = new double[N];
  }
  
  return 0;
}

Hello, could you explain me what this program does, it i hope locates one billion arrays in the dynamic memory and each of this billion arrys has one billion places for "int" variables?

Thanks in advance :)

[Catfish2]

It allocates a million double arrays that can each hold one million doubles.
Theoretically.

A double requires 8 bytes, so you try to allocate...
8 * 10⁶ * 10⁶ = 8 terabytes.

Do you have that much memory?

[Raezzor]

Funny thing is, it passes the address for each array to the same pointer. So you are leaking the memory for all but the last array.

[Nexius]

Please do delete[] all new[] memory.
Allocating memory without deallocating consumes your resources. You have a memory leak.