Ask HN: What helped you get good at programming?

  int foo (int n) {
    // pre: 1 <= n && n <= 10
    // post: 1 <= result && result <= 10
    return n * 10;
  }

  int foo(int n) {
    assert(1 <= n && n <= 10); // pre
    int result = 10 * n;
    assert(1 <= result && result <= 10); // post
    return result;
  }

  for i from 1 to size
    min = i
    for j from i+1 to size
      if a[j] < a[min] then min = j // not a good sort, don't do this at home kids
    swap a[i] and a[min]

  unitary_complex { real, imaginary }

  ui.real = 10; ui.imaginary = 20;

  total_cost = 0 
  bag = {}
  // invariant: total cost is always the sum of the cost of items in the bag
  // adding an item:
  bag.add(tv)
  total_cost += 1000 // only after this is the invariant true again