valgrind --track-origins=yes ./program test_input.txt
==8469== Memcheck, a memory error detector
==8469== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==8469== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==8469== Command: ./test5 test_input.txt
==8469==
Step: 1
==8469== Use of uninitialised value of size 8
==8469==    at 0x400629: main (in /home/bob/Dropbox/programs/program)
==8469==  Uninitialised value was created by a heap allocation
==8469==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==8469==    by 0x4005DD: main (in /home/bob/Dropbox/programs/program)
==8469==
==8469== Invalid write of size 8
==8469==    at 0x400629: main (in /home/bob/Dropbox/programs/program)
==8469==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==8469==
==8469==
==8469== Process terminating with default action of signal 11 (SIGSEGV)
==8469==  Access not within mapped region at address 0x0
==8469==    at 0x400629: main (in /home/bob/Dropbox/programs/program)
==8469==  If you believe this happened as a result of a stack
==8469==  overflow in your program's main thread (unlikely but
==8469==  possible), you can try to increase the size of the
==8469==  main thread stack using the --main-stacksize= flag.
==8469==  The main thread stack size used in this run was 8388608.
==8469==
==8469== HEAP SUMMARY:
==8469==     in use at exit: 36 bytes in 2 blocks
==8469==   total heap usage: 3 allocs, 1 frees, 1,060 bytes allocated
==8469==
==8469== LEAK SUMMARY:
==8469==    definitely lost: 4 bytes in 1 blocks
==8469==    indirectly lost: 0 bytes in 0 blocks
==8469==      possibly lost: 0 bytes in 0 blocks
==8469==    still reachable: 32 bytes in 1 blocks
==8469==         suppressed: 0 bytes in 0 blocks
==8469== Rerun with --leak-check=full to see details of leaked memory
==8469==
==8469== For counts of detected and suppressed errors, rerun with: -v
==8469== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
Segmentation fault