Good
Programming Practices- contd.
· Defensive programming: Prevent run-time errors by checking for
them before any risk operation. Never assume exact equality of real values. Produce a meaningful
error message directly related to the specific error. Never stop if something useful can
be done. Check to see that you handled the null cases properly.
· Use
of submodules: Protect input parameters. Avoid procedures with side- effects.
Make all temporary
variables local to the submodule where they are used. Where appropriate use signal flags to return
the status of a computation to the calling program.
· Program Independence: Try to develop programs that are
independent of: (a) the machine environment (portability) by using standard FORTRAN 77, by
avoiding machine dependent constants, by avoiding specific collating sequences, by
localizing and identifying unavoidable machine-dependent information. (b) The data set
(generality) by making key data values parameters to procedures not local variables,
by considering how to achieve generality from the earliest stages of program design and
specification.
· I/O
behavior guidelines: Always identify the input you are requesting. Avoid
programs that trap the user in an infinite loop demanding correctly structured input,
without offering assistance in preparing it. Use a “help” mode to aid users prepares input.
Have users supply input in a form most natural to them, not to the program. Use defaults to
reduce the amount of input data required for flexible programs.