Self study guide: Fortran 95 - University of Cambridge

If the last character of a line is an ampersand ‘&’, then it is as if the next line was
joined onto the current one (with the ‘&’ removed). Use this to lay out long
expressions as clearly as possible.
• Another technique is to split long expressions using intermediate calculations. A
simple example would be replacing something like:
res = sqrt(a + b*x + c*x*x + d*x*x*x) + &
log(e * f / (2.345*h + b*x))
with
t1 = a + b*x + c*x*x + d*x*x*x
t2 = E * F / (2.345*h + b*x)
res = sqrt(t1) + log(t2)
• Think about the choice of variable names. You can make the variable names very
clear with names such as energy or momentum. This can be very helpful, but
also cumbersome in long expressions. A useful rule of thumb is that if there is an
accepted symbol for a physical quantity consider using that (e.g. E and p); use
longer more descriptive names if one does not exist.
We will return to the topic of programming style later when we consider how the
program can be broken up into smaller units. This will be the main job in the next
section of the course.
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