Columns 73-80 were ignored by the compilers and could be used for identification or a sequence number so that if the card deck was dropped it could be restored to its proper order using a card sorter. Depending on the programming language, debugging output statements could be quickly activated and "commented out" by using cards with such statements punched with the comment character ("e.g.", 'C' in Fortran) in column 80 of the card; turning the card end-for-end would put the 'C' in the leading column, which transformed the now backwards card's contents into a comment while leaving the physical card in place in deck.