If the last line of data had been written as 'Eve,79,.,I,4', then the same statements could be used
with or without the DSD option.
When using an INFILE statement with incomplete data, you may need to use the MISSOVER option to
tell SAS to fill in missing values at the end of a line. For example, suppose that the teacher of the
class did not mark anything for absences when the student was always present, and the data set A:
GRADES.TXT looks like this: