# Switching from one-column to two-column with text justification in IEEEtran document class

I am using `IEEEtran.cls` for a write-up. I needed to include a `longtable` in the text spanning two columns, so I changed to `\onecolumn` in order to accommodate the table. After the table, I wished to return to two columns using `\twocolumn` at the end of the paper i.e., before acknowledgement section. Everything worked fine, however, the problem is, I observed that the text after the `\twocolumn` command is centered as shown in the following figure. How can I change this to the traditional IEEE justification, i.e., not center-aligned?

• `\twocolumn` doesn't affect text justification, you will have an error in the markup of the acknowledgement, but as you have given no indication of the code you used it is impossible to say what is wrong – David Carlisle Sep 24 '17 at 10:41
• Did you use the `\centering` directive for your long table, per chance? – Bernard Sep 24 '17 at 10:42
• @Benard, yes, I used the \centering directive for the long table – Abdulhameed Sep 24 '17 at 13:10
• @Mico, loading `\ragged2e` in the package preamble works with `\justifying` as you mentioned. Thanks – Abdulhameed Sep 24 '17 at 13:17
• not only are longtables centred automatically, `\centering`, `\raggedright` etc have no effect at all on `longtable` as the table is always the full width of the page, to allow page breaking. – David Carlisle Sep 24 '17 at 13:45

## 1 Answer

The crucial piece of information, which you provide in a comment in response to @Bernard's query, is that you use a `\centering` directive -- presumably to center the material in the `longtable` environment, right?

It appears to be the case that you failed to delimit the scope of the `\centering` directive (say, by surrounding its intended scope with `\begingroup` and `\endgroup`). Hence, the `\centering` directive applies to the entire remainder of the document, and not just to the `longtable` environment. Somewhat ironically, maybe, `longtable` isn't even affected by the `\centering` directive, as David Carlisle has pointed out in a comment. (`longtable` environments are set up to automatically occupy the full width of the text block; that's why centering them has no effect.)

The easiest, cleanest, and only sensible remedy is to simply omit the `\centering` directive.