[ILUG] OT: Elementary C question

[Michael Turley]

I'm probably chancing my arm here but I've been trying
to finish a bit swapping program. The program is
supposed to reverse the bit order in every byte of a
binary file (I want it actually to reverse the bits in
a 2 byte type but that can wait for the moment). 

The program seems only to process one byte and then
copy the rest of the file verbatim. 

I would be indebted if some good, or even indifferent,
C programmer take a quick look at the code to see if
they can spot the obvious mistakes. Any thoughts (and
I mean any!) are more than welcome. Cheers and
apologies for the OT nature of the mail!



#include <stdio.h>
#define BSIZE 1024

void main() {

	FILE *fin, *fout;
	
	char buf [BSIZE];
	int count;
        unsigned char c2;
        unsigned char d;                /*d will be c
reversed*/
        
        fin = fopen("little_end_file", "r");
	fout = fopen("new_big_end_file", "w");

	while ((count = fread(buf, 1, BSIZE, fin)) > 0) {

		
		d=0;
                c2=(char)*buf;
	
                if (c2>=128)    { /* If c2>=128 then
bit 7 is set */
                        d=d+1;  /*set bit0 of d */
                        c2=c2-128; /* clear bit7 of c2
*/
                };
                if (c2>=64)     { /* If c2>=64 then
bit 6 is set, etc. */
                        d=d+2;
                        c2=c2-64;
                };
                if (c2>=32)     {
                        d=d+4;
                        c2=c2-32;
                };
                if (c2>=16)     {
                        d=d+8;
                        c2=c2-16;
                };
                if (c2>=8)      {
                        d=d+16;
                        c2=c2-8;
                };
                if (c2>=4)      {
                        d=d+32;
                        c2=c2-4;
                };
                if (c2>=2)      {
                        d=d+64;
                        c2=c2-2;
                };
                if (c2>=1)      {
                        d=d+128;
                        c2=c2-1;
                };
	
		fwrite(&d, 1, count, fout);
	} 
fclose(fin);
        fclose(fout);
}
====================
The other problem that I am having is that I cannot
get fread/fwrite to deal with bytesizes larger than 1
byte (e.g. fwrite (blah, sizeof(int), blah, blah);
outputs zero characters from its corresponding
fread(blah, sizeof(int), blah, blah);[1])

[1]while ((count = fread(buf, 2, BSIZE, fin)) > 0) 
         fwrite(buf, 2, count, fout);

=====
Mr. Michael Turley
Gracious winner, Generous lover, All round great guy.
http://www.tribune.ie/mike
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