Ideas for introducing symbols for OOP in flowcharts

There is a standard UML class diagram for drawing object-oriented programming (OOP), but I thought it would be easier to explain if there was a symbol for OOP when explaining the main flow.

First of all, the existing flow diagram symbols alone cannot capture the flow of OOP in the following points.

・ Limitations of OOP support for existing flow charts

1. I don't know what I did for each instance in the main flow.
2. I don't know if there is no return value (void) in the operation of each instance, or what is passed when there is a return value.
3. I don't know what variables (properties) are prepared in the called object (abstract class) and what methods can be used.
4. I don't understand the relationship between object (abstract class) inheritance and interface inheritance.

So I devised a symbol to represent the instance. The following figure is an instance of the calculator object in the article Introduction of window operation program for object-oriented programming experience made with VBS that was uploaded to qiita before. It is a diagram showing the conversion.

The symbols used to represent the behavior of the instance on the main flow diagram are It becomes an expression like.

A flow chart that uses the symbols of this instance to express a simple process for operating two instances of a red calculator and a black calculator in cooperation with each other. It will be shaped like.

The Java language code in the form of this flowchart

Dentaku2 AkaDentaku = new Dantaku2();
Dentaku2 KuroDantaku = new Dentaku2();
AkaDentaku.tasu(2.0);
KuroDentaku.tasu(5.0);
AkaDentaku.kakeru(4.0);
Double a = AkaDentaku.tasu(0.0));
a += KuroDentaku.tasu(0.0));
If (a >= 10.0)
        System.out.println("The answer of the red calculator"+ AkaDentaku.tasu(0.0));
Else
        System.out.println("The answer of the black calculator"+ KuroDentaku.tasu(0.0));

is.

In order to express it as a flow chart without disturbing the analysis of the main flow, I thought that it would be good to introduce a flow chart symbol for OOP.

I put the draw image of this instance symbol in the PowerPoint slide of "Object-oriented programming introductory kit 2". I will. You can use it when you want to incorporate it into your own flow chart.