Minor issue: the second line of your first example is not needed as it just sets those variables to have the same values that they already had.

Major issue: You might as well delete all three lines of your last example as it does nearly nothing and none of the minor things that it does do have any use that I can see. The first example allows you to make use of the declared variables further down in the file. That is what you want. You last example doesn't do that. If you used your last example then you'd get errors in the code further down in the file that made use of those variables (and if there is no code further down that makes use of those variables, then you might as well drop them from the declaration).