After the analysis has been completed and the decisions have been made, the process passes on to the application programmer. The programmer is not given free reign, but rather must adhere to the specifications of the designer. However, given that the designer is probably not a programmer, there may be changes required because of programming limitations. But at this point in the project, we are not talking about design changes, merely changes in the way the program does what the designer specified it should do.

The development process is iterative, usually working at the module level. A programmer will usually follow this process:

1. Code a module.
2. Test a module for functionality.
3. Make corrections to the module.
4. Repeat from step 2 until successful.

After testing has been completed on a module, it is signed off and effectively frozen to ensure that if changes are made to it later, it will be tested again. When sufficient modules have been coded and tested, they can be tested together in tests of ever-increasing complexity.

This process is repeated until all of the modules have been coded and tested. Although the process diagram shows testing only after development has been completed, testing is continuously occurring during the development phase.