I have a function SetTFgr(float T, int FGr) to set the time and filtergrade of my LED enlarger.

It works without a problem and changes the values of T or Fgr according to the buttons I press. Both T and FGr are global variables.

Now I want to use the same funtion with different variables. When I call the function with SetTFgr(TExp[i], FGrExp[i]) I would expect the function to work with the values of TExp[i] or FGrExp[i] and increase/decrease these values. It does not, it appears to use the value of T or Fgr instead.

How can I get what I am after?