Getting a different output compared to sha256sum command about sha-2 HOT 1 CLOSED

Compiling your program and testing it, I get:

$ ./main
ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad

Creating a file with the same contents to compare with sha256sum, I get:

$ echo -n abc > tmp.txt
$ sha256sum tmp.txt
ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad tmp.txt

Looks consistent to me. You must be making a mistake somewhere, like having a line feed in your text file.

For the record, you do not need to redefine HASH_LENGTH. You can just use SIZE_OF_SHA_256_HASH instead.

from sha-2.