You have already learned about programs that work with arrays of integers, of integer pointers, of cylinders, and of cylinder pointers. Now, you learn about analyze_train, a program that works with an array of railroad-car pointers. The basic analyze_train program introduced in this chapter reads railroad-car–type numbers and displays a report listing railroad-car–type names.

The analyze_train program is a keystone program, because it brings together many concepts, including C++'s mechanisms for reading, displaying, testing, conditional execution, iteration, and pointer dereferencing.

Once you have learned about the basic analyze_train program introduced in this chapter, you will be ready to tackle many other C++ mechanisms, each of which is introduced in subsequent chapters through modifications to the analyze_train program. Some modifications expose more sophisticated ideas, such as inheritance through a class hierarchy and run-time function selection using virtual functions. Other modifications introduce commonplace mechanisms that have been skipped over so as to expose you to C++'s strengths more quickly.