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.