Lab04, CISC105 Summer 2005

Directions

Write a program for each of the following problems. If you wish, you may start each program using a previous program as a base and then modifying it, BUT you will learn more if you code each one from scratch. Be sure to save every separate program. All programs must be properly commented and indented (see Assignment Standards on the class website).
Some programs below are associated with a question. Answer the question using comments in your code.
During your scripting of the programs, you will compile and run each one. If a program does not compile, don't try to run it (because a.out will not have been created).
Name each program lab04.n.c, where n is the number in the list below. For example, the name of the file for the first will be lab04.1.c

Programs

(10) Write a void function that takes two parameters---a total width and a number of stars/asterisks---and prints the number of stars on one line, right-justified within the total width. Call the function from a main program that demonstrates the function's abilities.
Example output:
Right-justify 5 asterisks in 10 spaces
```
     *****
```
Right-justify 1 asterisk in 20 spaces
```
                   *
```
(10) Write a function that takes two parameters---the original value and a scaling factor---and returns the scaled value. Call the function from a main program that demonstrates the function's capabilities.
Example Runs:
```
Enter a number: 3.5
Enter a scaling factor: 30
Scaled value: 105

Enter a number: -1
Enter a scaling factor: 20
Scaled value: -20
```
(30) Modify angle.c to be more general and to use some of the concepts we've learned since we originally wrote the program.
- Let the user specify the start and end values for degrees, as well as the increment for the next degree.
- Add a function that converts degrees into radians. Use the function in your program.
- Use a loop to generate the output, from the user-specified start to end degrees in the user-specified increment.
In next week's lab, we'll put the above programs together to create a bigger program.

Creating a Web Page

A special directory is the one called ~/public_html. Any and all files that you put into this directory become available on your web page. (If your user id is foobar, your web page is http://udel.edu/~foobar).
To see if you have this directory, change your working directory to your home directory and then see if the directory "public_html" is listed. If you don't have the directory already, create the public_html directory.
Go into the public_html directory and create a cisc105 directory. The public_html/cisc105 directory will store your CISC105 web page. In a later step in this lab, you will create a personal web page (if you don't already have one) and a web page specifically for this course.
The files for your personal web page go into the directory "~/public_html", and will be accessed via the URL http://udel.edu/~userid (where userid is your UDelNet ID).
The "CISC105 web page" goes into the directory "~/public_html/cisc105" and will be accessed with the URL http://udel.edu/~userid/cisc105. You can use this same technique to create as many web pages as you like under your main web page, just by creating new subdirectories to store the content.

Goal 1: Creating a personal web page (10)

If you already have a personal web page on strauss (one that comes up when you type http://udel.edu/~userid, where userid is your UDelNet ID), then skip to the next goal (creating your CISC105 web page). Otherwise, cd into your ~/public_html directory.

Use emacs to create a file in that special directory. The file must be named "index.html". The contents of that file should be something like the following:

<html> <head> <title>Joe Sample's Web page</title> </head> <body> <h1>Joe Sample's Web page</h1> I had to do this <b>web page</b> for my <a href="http://udel.edu/~pconrad/cisc105">CISC105 class</a>. Right now it is pretty lame, but I hope to make it better later. </body> </html>

Here's what that looks like once it is formatted by a web browser:

Joe Sample's web page
I had to do this web page for my CISC105 class. Right now it is pretty lame, but I hope to make it better later.

After you save the file, you need to type in the following command:

chmod a+rx ~/public_html/*

This command makes all files and directories in your public_html directory accessible to all users on strauss, as well as all users on the World Wide Web. You need to repeat this command each time you add new files under public_html that you want users of the Web to be able to access.
More details:The asterisk in the above command is a "wildcard" that matches every file name in the public_html directory. You can also use chmod on individual files and directories as shown in class. You need to repeat this command each time you add new files under public_html that you want users of the Web to be able to access.
To see that it works, type into a web browser:
```
http://copland.udel.edu/~userid
```
If it doesn't come up, make sure you set all your file permissions correctly. The most common problem is not doing the "chmod a+rx ~/public_html/*" command. If you did that, and it still doesn't work, check with your TA or with a classmate for help.

Goal 2: Creating a CISC105 web page (10)

cd into ~/public_html/cisc105. Now, create an index.html file in this directory containing html code similar to the personal page.
Now, add an image to your web page. Find an image on the Web (or from wherever you want) and copy it into your public_html/cisc105 directory. Then, put the image in your CISC105 Web page, using the HTML tag <img src="imagename.jpg">, where "imagename.jpg" is the (case-sensitive) name of your file.
After you have created the index.html file and/or copied your image file into your public_html/cisc105 subdirectory, you may need to repeat the chmod a+r [filename] command to get the web page to come up when you use the URL http://udel.edu/~jsample/cisc105.

Goal 3: Why are you here? (30)

Several of you have mentioned that you're not sure why you have to take the course for your major. I, of course, believe that the course is just plain fun, so you shouldn't need a reason.

Computers and programming specifically have advanced all sciences. For example, researchers in other fields use computer programs to write simulations before performing expensive experiments in real-life. Computer programs are also used to process data quickly. Computer programming is a very useful skill!

Your assignment: Find at least two Web pages that discuss the connection between your major and computer science. (If you don't have a major, pick a potential major or find some sites about computer science that interest you.) Add these links to your cisc105 web page. Summarize what you learned from each link in a little blurb.

Searching the Web:

Google

The goal of this assignment is not to learn HTML, but if you would like to learn a little more about HTML to format your page nicer, there are many resources available:

You can find many, many more if you do a Google search.

Submission

You should have a total of 3 programs named lab04.1.c to lab04.3.c. Make a single script file (see lab00 for the instructions) where you cat, compile, and run each one in its final form (if it didn't compile, don't run it in the script - mark the place in the printed script file with a marker so it stands out).

Note: Cat, compile, and run each program in order! Do not cat all programs, then compile, etc.

Execute your program multiple times to show that you tested the program well.

Submission

Email the tar file to Gang by midnight on Wednesday (see lab00 for directions). Give the paper version to Gang at the beginning of your next lab. Clearly write at the top of your paper submission where Gang can find your web page.

Grading

Grading is as noted above for each program, and creating the web pages is worth 50 points for a total of 100 points. (Using UNIX, e.g., changing file permissions, is included in the 50 points.)

The "Creating a Web Page" part of this lab was adapted from Phill Conrad's lab.