Compile and run the main program ``schdebug.c'' in Appendix A with your schint() routine. This program inputs E and then calls your schint() routine with N=100, k1=0, k2=N, Psi=0, Psip=1, and V=-1/r. The program then prints out both your solution and the analytic solution at E=-0.5, which is r[k]*exp(-r[k]), and the ratio between these solutions. Finally, the program integrates backwards, calling your schint() routine with N=100, k1=N, k2=0, Psi=0, Psip=1, and V=-1/r, and printing a summary of the results.
Thorough debugging requires that you verify all of the outputs of the routine. In this case, schint() returns three separate quantities, which you should verify as below.