C - Message digest, same value returning every time (1 of 4 files should have a different value)

Question

One of my files should be different than the others and this program is supposed to tell me which. I have a feeling that the "_setmode..." could be wrong (actually almost sure, it doesn't seem to have any effect - it's supposed to set input mode to binary at the start of the program). To test, I'm resetting the program after each use and renaming the text files so they are all tested with the same name. I'm using C:/Users/User/Desktop/file.txt as my DOS command.

#include <stdio.h>
#include <fcntl.h>
#include <io.h>

int main(void){
    int s1=0, s2=0, s3=0, s4=0;
    int m1=3, m2=7, m3=13, m4=23;
    int B;
    _setmode(_fileno(stdin), _O_BINARY);

while((B=getchar()) != EOF)
{

   s1 = (s1 + B*m1) % 256;
   s2 = (s1+s2 + B*m2) % 256;
   s3 = (s1+s2+s3 + B*m3) % 256;
   s4 = (s1+s2+s3+s4 + B*m4) % 256;
   B = getchar();
   printf("%02x%02x%02x%02x\n", s1, s2, s3, s4 );
}
return 0;
}

Files I'm using (pastebin with pastebin links to files since I need more rep to post more than 2 links):

File Links: http://pastebin.com/wLF9NRNu

I also just found out that I'm apparently only supposed to be checking the midpoint value, so I was given the following command, which seems more or less useless to me:

C:\ > mdPoint < file.txt

Also after playing with it some more, it seems my commands aren't opening the files at all and is just giving me output based on the command text I enter. Not sure what's up with that.

Answer 1

Not an answer but too much for a comment. I tested your program on three files. The first file test1.txt contains the text "one".

yourprogram < test1.txt
4d5646e2
7c95787e

An identical file test11.txt has the same content "one" and the same result.

yourprogram < test11.txt
4d5646e2
7c95787e

The next file test2.txt contains the text "two".

yourprogram < test2.txt
5c88c818
a93a4e42

So your comments about the result being "based on the command text" are incorrect, it works off the content. Perhaps you need a better thought out and presented question. And your pastebin does not contain anything easily accessible.

Answer 2

You had some errors in your code. I believe you mean the following:

#include <stdio.h>
#include <fcntl.h>
#include <io.h>

int main(void){
    int s1=0, s2=0, s3=0, s4=0;
    int m1=3, m2=7, m3=13, m4=23;
    int B;
    _setmode(_fileno(stdin), _O_BINARY);

    while((B=getchar()) != EOF)
    {

       s1 = (s1 + B*m1) % 256;
       s2 = (s1+s2 + B*m2) % 256;
       s3 = (s1+s2+s3 + B*m3) % 256;
       s4 = (s1+s2+s3+s4 + B*m4) % 256;

    }
    printf("%02x%02x%02x%02x\n", s1, s2, s3, s4 );
    return 0;
}