cmp_string compares two strings and returns an integer representing a boolean representing whether or not the two strings are identical.

string a  string b  expected return value
--------  --------  ---------------------
eecs      eecs      0
eecs      EECS      non-zero
eecs      eec       non-zero
eecs      (null)    (error-handling routine)

Here are the results of the test:

$ ./cmp_string 
comparison of "eecs" and "eecs": 0
comparison of "eecs" and "EECS": 1
comparison of "eecs" and "eec": 1
cmp_string: cmp_string.c:72: cmp_string: Assertion `(char_ptr_b != ((void *)0))' failed.
comparison of "eecs" and "(null)": Aborted