Sorry for the title if it is inaccurate, I don't really know the name of what I'm looking for
Suppose I have this class:
public class Potion(){
public int WaterAmount;
public int ReagentAmount;
}
Now if I wanted a method to check the amount of water or the amount of reagent in the potion I would have:
    public int GetWaterAmount ( Potion pot ){
    return pot.WaterAmount;
    }
    public int GetReagentAmount ( Potion pot ){
    return pot.ReagentAmount;
    }
Now my question is how can I combine these 2 methods into one so that I can just enter the parameter of the liquid I want to check for? Here's some invalid syntax of what I was looking for:
    public int GetAmount ( Potion pot, int SelectedLiquid){
    return pot.SelectedLiquid;
    }
    void main(){
    GetAmount(pot, WaterAmount);
    GetAmount(pot, ReagentAmount);
    }
In essence how can I make a parameter (selectedliquid) refer to different variables in a class (wateramount or reagentamount) ?
Or is this not possible and I do need to have 1 method for each variable I want to check for?