How do I change a global variable through is name as string?

I want to create a function that work on a global variable with the name exported through a parameter as string (just to use the same function with A LOT of variables).

Just say that the function that I want to create is called "Var + 1"; when I call that function I specify the parameter 0 as "A" (the name of a variable) and I want the function to add 1 to that variable; if I specify "B" I want it to add 1 to B and so on...

Is it possible? Or do you know other ways to do something similar?