These lines of code have been written as part of course CS50_fall 2018 reference to Problem set 4
Codes have been partially provided by Harvard and purpose was to implement lines of code focusing on using pointers. Both hash_speller & trie_speller do the same task. The difference is that former is implementing a hash_table data structure to load the dictionary while latter uses a trie data structure.
However, their functionality is that they load a dictionary and check a text_file for misspellings. try:
$ make speller
$ ./speller lalaland.txt