Avoiding "variable might not have been initialized"

Question

I recently ran across a routine that looks something like this:

procedure TMyForm.DoSomething(list: TList<TMyObject>; const flag: boolean);
var
  local: integer;
begin
  if flag then
    //do something
  else local := ExpensiveFunctionCallThatCalculatesSomething;

  //do something else
  for i := 0 to list.Count do
    if flag then
      //do something
    else if list[i].IntValue > local then //WARNING HERE
        //do something else
end;

This gives Variable 'local' might not have been initialized even though you can tell by reading the code that you won't hit that line unless the code branch that initializes it has run.

Now, I could get rid of this warning by adding a useless local := 0; at the top of the procedure, but I wonder if there might not be a better way to structure this to avoid the issue. Anyone have any ideas?

Answer 1

I would separate it into two for-loops--one for when flag is true and one for when flag is false. As an added benefit, you won't have to execute the if-statement on every iteration.

Answer 2

IMO, the assignment to 0 isn't useless here - it's beneficial to maintanability. So you'll save someone (perhaps your future self) from having to spend a minute or two to determine that the code works. And the design cleverness will likely be lost on them (even if it's you!)