Chapter 10

Section 10.1

• programs go through three stages – development, use and maintenance
• new program created in development stage
• version made available to users is initial release of program
• software maintenance is process of modifying a program to fix or enhance it
• eventually programs outlive their usefulness – considered program’s retirement from active use
• small changes during development will greatly reduce effort needed during maintenance
• goal of writing good software is to minimize effort to create and maintain a program, not just minimize time to develop it
• programmers create initial version, then modify it until it reaches some level of acceptance – build and fix model
• need to address requirements, design and testing – this is waterfall model
• no matter how carefully a program is designed, there is always a time when developer realizes a decision was an error, so need flexible development
• need iterative process so can cycle through development stages – waterfall model with backtracking – this will correct problems uncovered during development

Section 10.2

• a prototype is a program or representation created to explore some concept – programmers use them to explore ideas of a task
• it can just be a set of diagrams, or maybe pseudo-code
• discarded after used – not actual program

Section 10.3

• running a completed program with various inputs to find problems is testing
• can do walkthroughs on code with a group of people
• try to test looking for defects – defect testing
• test case is set of inputs, actions and expected output
• should be properly documented so it can be repeated
• developers sometimes make entire test suite – a set of test cases
• black box testing treats program as a black box, without regard to what’s inside
• white box testing exercises the internal parts of the program

Section 10.4

• Figure 10.7
• refinement scope is set of issues addressed in a refinement cycle
• allow programmer to focus on specific issues, not entire system at once
• can then begin design stage – lay out all requirements and associate them with the software – this defines objects
• then define classes by finding relationships – find inheritance, composition and general association
• then identify all methods of classes
• implementing it, then, should completely represent this design
• then test