`CISC181 honors, 02/14/06


Happy Valentines Day.

===a program that reads from a file=====

Modified to do average, min, max

we will return to this

====Info about Cygwin=======

Last time, we had some network issues, and so we switched to
running programs on my Windows PC using Cygwin.

A reminder: information about Cygwin is available
on the course web site:

http://www.udel.edu/CIS/181h/pconrad

Go to the upper left hand corner, to the link UnixAtUD

The page that comes up has a link with information
about Cygwin.

If you have any questions or comments about cygwin,
post them to the discussion boards on WebCT.

====Questions from Lab=====

Were there any unresolved questions from lab

how to print ?

  qpr -q whlps filename

from pc at home running Secure Shell SSH
  
  kpr filename



====Last time=====

Because of the interruption a few points may have
gotten lost.  Let's review:

Under the folder:

http://www.udel.edu/CIS/181h/pconrad/06S/lect/02.09

(Also available on strauss as:

/www/htdocs/CIS/181h/pconrad/06S/lect/02.09 )

There is a folder

  an.incorrect.program/goodCode02.cc

containing:

   goodCode02.cc

Let's look at that code again (I've copied it into today's folder)

We can compile it with:

  make goodCode02

That gives us an executable called "goodCode02", which we can
run with

./goodCode02

We might find entering numbers from the keyboard repetitively
to be tedious, so we can read from a file instead:

So, the program fileOfInt.cc shows how to read those numbers
from a file instead:

> make fileOfInt
CC    -o fileOfInt fileOfInt.cc 
> ./fileOfInt
Sorry, I could not open infile.dat
> 

We have to actually have a file called infile.dat.
A unix trick to make a quick file without going into
the editor is "cat > filename"

For example:

> cat > infile.dat
3
5
6
1
> 

You hit "CTRL/D" to terminate the input.

> ./fileOfInt
Sorry, I could not open infile.dat
> 

Strange, we already created infile.dat

We look at the code, and find a bug...

  A mismatch between what we are opening "nums.dat",
  and what is in the error message "infile.dat"


How could we have prevented this bug?

  one suggestion: maybe there is some way to
  determine the "nums.dat" from the infile variable
  e.g. something like 
      infile.name()
   I don't know if such a thing exists, but if
   it does, it's a terrific idea.
     @@@NOTE TO SELF@@@ look into whether this exists.

  another suggestion:  
      #define

   copy from fileOfInt.cc to fileOfInt2.cc
   and show how to use a #define

> cp fileOfInt.cc fileOfInt2.cc
> emacs fileOfInt2.cc

Then we changed fileOfInt2.cc to use a #define

===more code from last time to look at===

  @@@ look at each of these @@@

 readInt4.cc
 readNums1.cc