Assuming vi is a container of ints that includes even and odd values, predict the behavior of the following loop

#include <vector>

int main() {
  //std::vector<int> vi{1, 2, 3, 4};
  std::vector<int> vi{2, 4};

  // If the container contains any odd values, the loop will continue
  // infinitely.
  auto iter = vi.begin();
  while (iter != vi.end()) { // The loop body should be a block.
    if (*iter % 2)
      iter = vi.insert(iter, *iter);
    ++iter;
  }

  return 0;
}