C.21. Wrap-Up

This appendix presented basic problem solving for building classes and developing methods for these classes. We demonstrated how to construct an algorithm (i.e., an approach to solving a problem), then how to refine the algorithm through several phases of pseudocode development, resulting in Java code that can be executed as part of a method. The appendix showed how to use top-down, stepwise refinement to plan out the specific actions that a method must perform and the order in which the method must perform these actions.

Only three types of control structures—sequence, selection and repetition—are needed to develop any problem-solving algorithm. Specifically, this appendix demonstrated the if single-selection statement, the if...else double-selection statement and the while repetition statement. These are some of the building blocks used to construct solutions to many problems. We used control-statement stacking to total and compute the average of a set of student grades with counter- and sentinel-controlled repetition, and we used control-statement nesting to analyze and make decisions based on a set of exam results. We introduced Java’s compound assignment operators and its increment and decrement operators. We discussed Java’s primitive types.

We demonstrated the for, do...while and switch statements. We showed that any algorithm can be developed using combinations of the sequence structure (i.e., statements listed in the order in which they should execute), the three types of selection statements—if, if...else and switch—and the three types of repetition statements—while, do...while and for. We discussed how you can combine these building blocks to utilize proven program-construction and problem-solving techniques. We also introduced Java’s logical operators, which enable you to use more complex conditional expressions in control statements. In Appendix D, we examine methods in greater depth.