PPT Slide
There is a tendency for a programmer to code lists of possible values of a variable directly into the program(e.g. three possible colors, blue, red and yellow). If the application subsequently requires that the color green be added as a possible value then the program must be changed and re-compiled and re-distributed to the customer base. Instead the list of values should be kept in a file(or table) external to the program which may be maintained independently. In many cases the additional value may be added to the table and there may be no requirement to change and re-compile and re-distribute the program.
These examples illustrate that effective programming techniques can result in significantly lower costs in developing and maintaining applications which translates into lower costs and better responsiveness to problems.