In practice, “pure” bottom-up development is not possible; the construction of new elements must always be guided by a look-ahead to the requirements of the eventual program, and even then it will often be discovered at a later stage that some earlier construction sequence was inappropriate, leading to a need for iteration. Compare top-down development.
"bottom-up development." A Dictionary of Computing. . Encyclopedia.com. (March 11, 2019). https://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/bottom-development
"bottom-up development." A Dictionary of Computing. . Retrieved March 11, 2019 from Encyclopedia.com: https://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/bottom-development