By now, you have probably noticed the rhythm of development: add features, develop features, refactor, retest, and repeat. It is time once again to shift things around in the example.
Figure 15.1 shows the new organization. Accumulator(), Tape(), and the parts of main() that interact with the user have each been moved into their own modules. These three modules are all in the SAMSCalculator namespace.
The arrows show how the functions call each other. main() calls CalculateFromInput(), which calls Accumulator() and Tape(). main() can also call functions in the other modules.
After this ...