hamming.c -- my implementation of the encode function, with some
auxiliary routines such as for printing an integer's bit
representation

my_encoder.c -- when linked with a hamming.h implementation, provides
a front-end for the encode function: accepts a hex integer as a
command-line argument representing the text and prints out the
codeword, also in hex

my_decoder.c -- analogous to my_encoder.c, but for the decode function

my_invert.c -- when linked with a hamming.h implementation, this
program checks that the program decodes corrupt
codewords. Specifically, for a large (million or so) number of text
words x, the program takes encode(x), and for each of 31 bits it flips
a bit to form encode(x)', then verifies that
x=decode(encode(x)'). When it encounters an error indicates the text
and which bit was flipped. Stops at 50 errors.

test 1 & 2 tested whether the student's program encoded and decoded
properly the words supplied in the provided testdata.txt. test 3 used
my_invert as described above.