creating an src directory with a CalculatorApp package and class
creating addition and subtraction methods in the java class
creating multiplication and division methods in the CalculatorApp class
working out main menu choice text
adding error cchecking for choice selection
made a method for the calculator menu and added a main method
adding method to check for double values
adding switch statement to handle menu choices
finishing switch statement options
working on choice to quit
CalculatorApp is finished