I wish that someone can help me with the following problem:
I have an integer and a button.
After clicking on the button, the integer value would be for example 10.

Then how could I store that value 10 into the memory, and when I click the button again, the new integer value now is 5. I'd like to add up the old and new value together and write it to a text file.

Thank you. Other way to achieve the same goal is appreciated. Please help.