vardef numbers = array<int>(10) [
  1, 3, 0, 2, 0, 0, 4, 5, 0, 7
];
vardef tgt = 0;
vardef src = 0;
while src < len(numbers) {
  if numbers[src] != 0 {
    numbers[tgt] = numbers[src];
    tgt = tgt + 1;
  }
  src = src + 1;
}
while tgt < len(numbers) {
  numbers[tgt] = 0;
  tgt = tgt + 1;
}