CS60 Homework Assignment 8
-----------------------------

Due: Oct 24th at 1:00pm

BMP Header Reader
------------------------

The task of this assignment is to write a simple program that takes a
bmp image file as a commandline argument, reads the file's well
defined header information, and finally displays the parts of the
header individually for the user.  The format of a valid bmp file's
header can be found by following the link below or on the CS60 website:

http://www.fastgraph.com/help/bmp_header_format.html

Hints:
-----------------

Chapter 3 in Stevens, Chapter 8 in K&R

All of the header elements are <= 4 bytes, so the 'int' type is big
enough to hold each element.

Commandline arguments in C are handled as parameters passed to the
'main' function.  Simply define your main as:

int main(int argc, char **argv) {
...

And any arguments given to the function on the shell command line will
be passed to the main function.  The first argument, argc, is simply
the number of argmuents that were input by the user.  The second
argument, char **argv, is a list of strings (can also be specified
'char *argv[]' if you wish).  Each argument is a string in argv,
starting with the name of the executable itself.  For instance, if my
commandline was:

./hw8 foo.bmp la la goof

Then in the program:

argv[0] points to "./hw8"
argv[1] points to "foo.bmp"
argv[2] points to "la"
argv[3] points to "la"
argv[4] points to "goof"

and of course argc is set to the value 5.

Turnin
--------------------

The turnin tag for this assignment is 'hw8' and must contain the code,
a typescript showing the program compiling (with -ansi -pedantic)
without warnings and running on at least 'mc6.bmp' and 'wut.bmp' from
the webpage, and an optional README.

Extra Credit
--------------------

For 1pt extra credit, implement error checking in your program for the
following scenarios:

1.) no file specified on the cmdline
2.) file does not exist/cannot be opened
3.) corrupt header (file < 54 bytes)

Sample Output
--------------------
[root@localhost hw8]# gcc -ansi -pedantic hw8.c -o hw8
[root@localhost hw8]# ./hw8
USAGE: ./hw8 <bmpfile>
[root@localhost hw8]# ./hw8 mc6.bmp
Header Info for mc6.bmp
------------------
sig: 19778
sizefile: 864054
res1: 0
res2: 0
imgoffset: 54
sizehead: 40
width: 720
height: 400
numplanes: 1
bpp: 24
comptype: 0
sizedata: 864000
hres: 2834
vres: 2834
numcols: 0
numicols: 0
[root@localhost hw8]# ./hw8 wut.bmp
Header Info for wut.bmp
------------------
sig: 19778
sizefile: 286194
res1: 0
res2: 0
imgoffset: 54
sizehead: 40
width: 334
height: 285
numplanes: 1
bpp: 24
comptype: 0
sizedata: 286140
hres: 2952
vres: 2952
numcols: 0
numicols: 0
[root@localhost hw8]# ./hw8 foo.bmp
ERROR: corrupt img header
[root@localhost hw8]# ./hw8 dur.bmp
ERROR: cannot open file dur.bmp
[root@localhost hw8]# ls *.bmp
foo.bmp  mc6.bmp  wut.bmp
[root@localhost hw8]#