Cannot find the temporary files when executing the compiled C++ code [on hold]

I have just tried to execute a scientific code from other people. This code is written in C++ and has MPI functionality.

The nightmare is that the program is eating my disk memory. However, the output result files are not so large.

When I run this program, it is printing numbers intensively; I guess the program is saving something in some temporary files.

By the way I am using Ubuntu 14.04 LTS.

The system cannot be restarted last time, for the reason no much memory. I entered in the recover mode to delete something. Thank god nothing is lost.

I really hope someone could help me find the nasty temporary files.