Creating the class STCalculator
After you define the application, the next step is to define a class within the application STCalculatorApp. This new class will contain the Smalltalk code to implement the calculator. You can create this class from the Applications Browser: 
1.	Select (Object) in the classes pane. 
2.	From the Classes menu, select Add > Subclass. 
3.	Type STCalculator. As before, you might have to rename the class if STCalculator already exists. 
The following window appears: 

4.	Select subclass and select OK. 
That’s it. You’ve created your first Smalltalk class.
Last modified date: 03/26/2020