1) What must occur before a file can be read or written? 2) What is the range of the valid unit numbers for a file open? 3) For the following statements: integer :: opnstat character(20) :: filename-"file.txt" open (14, file=filename, status="old", action="read", position="rewind", iostat-opnstat) if ( opnstat > 0 ) then write (*, *) "Error, can not open file." stop end if a) What is the name of the file being opened? b) What is the unit number that will be used for subsequent write operations? c) Does the error message get printed if the file does not exist (yes/no)? d) What does it mean when the status variable is > 0?

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, computer-science and related others by exploring similar questions and additional content below.