In this exercise you can practice operating with arrays without using
do loops.
Start with the skeleton code array-syntax.F90 and
initialize the provided array a to 0.1, 0.2, 0.3, ... and the array
dif to 0.0. Do not use do loops ("implied do" is ok).
Next, calculate the difference between two successive elements of a
dif(i) = a(i+1) - a(i)
using array syntax, i.e. without a do loop.