1) Wow, a single nonimportant warning even on my paranoidal setup! Good.
3) Bug on line 26: does that semicolon need to be here?
2)
Those '/n's... a) they are not newline symbols, b) they have no effect. It looks like they are here to separate blocks of code, but comments or empty space will do that better.
unsigned stuff in loops creates signed/unsigned mismatch. You should use signed type as size is signed too. for (unsigned col = 1; col <= size; col*2, col++){ marked part does not do anything at all.
As is, the if statement is unnecessary.
If the OP intended to conditionally increment round as a method of detecting that the cin failed, that would work on the first round, but not subsequent rounds. The OP does check for the success of the cin at line 29, so relying on round to detect a cin failure is unnecessary also.