The stack is the first module of the calculator that we will design and implement. Although I defined the module’s public interface in Chapter
2, I said very little about its implementation. In C++, the module is not a defined language concept. Therefore, we are essentially left to decompose the stack into a logical grouping of functions and classes and call this our module. Hence, this is where we begin. If you’re a little rusty on the mechanics of the stack data structure, now would be a great time to consult your favorite data structures and algorithms book. My personal favorite is the one ...