How to declare a global variable that could be used in the entire program

Question

I have a variable that I would like to use in all my classes without needing to pass it to the class constructor every time I would like to use it. How would I accomplish th

Answer 1

While I would like to avoid global variables like the plague as our software cannot be multithreaded effectively due to the high reliance on global variables, I do have some suggestions:

Use a Singleton. It will allow you to keep the code and access clean. Part of the problem with a global variable is you don't know what code has modified it. You could set the value of global somewhere in your function relying on the hope that no one else will change it, but function your code calls, fooA, changes it and now your code is a) broken, and b) hard to debug.

If you have to use a global variable without touching the singleton pattern, look at fupsduck's response.