Chapter 16 // Exercise 9 - Principles & Practice Using C++

In this exercise I am using Visual Studio 2017 and modified versions of the graphics files used throughout the chapters. You can find those versions through the link below.

Chapter 16 // Exercise 9

Modify the calculator from Chapter 7 to get its input from an input box and return its results in an output box.

Github: https://github.com/l-paz91/principles-practice/tree/master/Chapter%2016/Exercise%209

Oh I wish this chapter would stop haunting me. Looking at the code though reminds me of how eager I was to put in error messages. Now I just don't care.

I also wanted to avoid messing with get() and unget() as much as possible so I googled how to put a string into cin and found this very handy section of code:

https://stackoverflow.com/questions/3797280/injecting-string-to-cin

This uses istringstreams and effectively "fakes" typing in the keyboard. The calculator code thinks we've typed into cin and will happily go about getting and putting back characters in cin.

I did remove a few functions and moved definitions into a cpp file (with declarations in the header) but for the most part it has stayed intact from the code uploaded here:

https://raw.githubusercontent.com/l-paz91/principles-practice/master/Chapter%207/Exercise%209

You can both type statements into the calculator (just don't type '=' press the button) and press the buttons: