The archive file diffprob.zip contains the files:
readme.txt | general information |
areash.pdf | Computing the surface area of a Sears-Haack body |
areash2.pdf | Numerical details |
areash.f90 | Program for computing surface area |
geopot.pdf | What is geopotential altitude (and why?) |
hydro.pdf | Equations of hydrostatic equilibrium |
oshock1.pdf | Wave angle for a given Mach and deflection angle |
oshock2.pdf | Numerical details |
oshock.f90 | Program for computing oblique shock |
None of these are what we call production programs. You can simply run them and modify them as needed to help you understand the problem.