# Uses a binary search algorithm to locate a value in the specified array.
binary_search: (items, value) =>

  start: 0
  stop:  items.length - 1
  pivot: Math.floor((start + stop) / 2)

  while items[pivot] isnt value and start < stop

    # Adjust the search area.
    stop:   pivot - 1 if value < items[pivot]
    start:  pivot + 1 if value > items[pivot]

    # Recalculate the pivot.
    pivot: Math.floor((stop + start) / 2)

  # Make sure we've found the correct value.
  if items[pivot] is value then pivot else -1


# Test the function.
print(2 is binary_search([10, 20, 30, 40, 50], 30))
print(4 is binary_search([-97, 35, 67, 88, 1200], 1200))
print(0 is binary_search([0, 45, 70], 0))
print(-1 is binary_search([0, 45, 70], 10))