errors on modifying lj/cut and mpirun

Hello, LAMMPS users & Developers
I modify the pair_lj_cut.cpp /*.h. When I run mpirun -np 1 lmp_mpi<, it works.But there’s a message below

segmentation fault usually means, there is a programming error.
they can happen very easily in programming languages like C/C++ or Fortran.
even in the 1 MPI task case, you do have a segmentation fault, and thus there is a programming error in your code.
there are lots of ways and it is well documented how to debug your code and locate memory access issues.
popular options are to compile the binary with the -g flag and then enable core dumps and investigate the core dump.
or use a memory access checker tool like valgrind with the memcheck tool.

this is in the basic programmer skill set and thus off-topic for this mailing list. you can search the web or ask colleagues with more experience in programming/debugging C++ code, and you will probably find (much) more help than you need.