ShoesCalculator

A little app we're going to modify to learn some Ruby basics

INSTALL

• Get a copy of Shoes running, resources online at:

https://github.com/shoes/shoes/wiki/Building-Shoes

http://shoesrb.com/manual/Installing.html

I had to add the following line to my ~/.bashrc to get this running on OSX:

PATH=/Applications/Shoes.app/Contents/MacOS:$PATH

• Fork your own copy of this exercise and clone it

• Run shoes with the following command, from the directory you just cloned into

shoes calculator.rb

TODO

Over to you. Work through the following improvements and see if you can figure out how to achieve them. Each time you make a change, commit and push your code to your GitHub account.

1. Fix the layout so that the numbers run from 0-9 in rows, e.g 7-8-9
2. Refactor your code. Where might we use a case statement to simplify our solution?
3. Implement a cancel entry (C) button that clears the input
4. Implement other scientific calculator functions, e.g. power of two, power to a given number, square root etc.
5. Try experimenting with the user interface, changing colours, layouts and backgrounds and gradients
6. Fix the problem where the inputs are treated as integers, not floats, so that we can get correct results. See if you can have the input keep its integer values. Hint - ask us for help!
7. See if you can change the label of the operator buttons to use the mathematical division label, whilst keeping division function working.

Homework

Using Shoes or a text-based terminal application, create a trip calculator. Ask the user (politely) for four inputs:

• Distance – how far will you drive?
• MPG – what is the fuel efficiency of the car?
• $PG – how much does gas cost per gallon?
• Speed – how fast will you drive?

Your output is a string: “Your trip will take 3.5 hours and cost $255.33.”

For every 1 MPH over 60 MPH, reduce the the MPG by 2 MPG. (i.e. a car that normally gets 30 mpg would only get 28 mpg if its speed were 61 mph. Handle the case that this value gets below zero).

Homework Extensions

Bonus points for creating another calculator or amending your calculator with the following features:

• Mortgage calculator: Calculate the monthly payment when given the other variables as input.
• BMI: Calculate the BMI when given the height and weight.

Submission

Once you're done, submit a pull request so that I can review your work.