COP3832, Fall 1999, Perl Assignment 1

Due Tuesday 9/28 at the start of class

You may run examples of these scripts from this location: Running Examples. You must have a Java enabled browser.

Read chapter 2 of the Learning Perl book. Write a Perl script that does the following. Please create the script on mongoose.

Prompt the user and read in two scalar values.
Display the values as they were entered, but within double quotes so that any leading or trailing white space will be identifiable.
Use chomp on each scalar and display them again, as above.
Display each scalar as a number, and display the sum of the two numbers.
Treat the scalars as strings and print their concatenation. (Use the . operator).
Treat the first scalar as a string and the second as a number and print the first repeated the second number of times. (Use the x operator).

Here is a sample of the output

Please enter something: 12we3
Please enter something else: 3er4

Here is the input
	something: "12we3

"
	something else: "3er4

"

Here is input after chomp
	something: "12we3"
	something else: "3er4"

Here is the input treated as numbers
	something: "12"
	something else: "3"
	12 + 3 = 15


Here is the input treated as strings, and concatenated
        "12we3" . "3er4" = 12we33er4

Here is the first repeated the second number of times
	"12we3" x "3" = "12we312we312we3"

Read chapters 3 and 4 of the Learning Perl book. Write a Perl script that does the following. Please create the script on mongoose.

Read a list of numbers (on separate lines) until the user enters -1.
Print the list of numbers entered by the user. Do not use a loop for this part.
Print the list of numbers entered by the user in reverse order. Do not use a loop for this part.
Print the largest number that the user entered. You will need a loop for this. Do not use the sort function.
Print the smallest number that the user entered. You will need a loop for this. Do not use the sort function.
Print the average of the numbers entered.
Print all the numbers that are above the average. You will need a loop for this.
Warning: if the user enters -1 as the first number, then the output should only say that no numbers were entered. Do not calculate the largest, smallest and average numbers for this situation.

Here is a sample of some output

Enter a list of numbers (-1 to stop)
15
32
12
44
56
16
10
21
21
31
-1

Here is the list of numbers you entered
15
32
12
44
56
16
10
21
21
31

Here is the list of numbers you entered in reverse
31
21
21
10
16
56
44
12
32
15

Here is the largest number: 56

Here is the smallest number: 10

Here is the average: 25.8

Here are the numbers above the average 25.8
        32
        44
        56
        31

Read chapter 5 of the Learning Perl book. Write a Perl script that does the following. Please create the script on mongoose.

Create a hash consisting of name and value pairs of your choice. Be sure there are at least 6 pairs in the hash.
Without using a loop, print all the keys of the hash.
Without using a loop, print all the values of the hash.
Use a loop to print out a list of each pair. Each pair should appear on a separate line.
Delete two elements from the hash.
Again, use a loop to print out a list of each pair. Each pair should appear on a separate line. (If you read ahead, you could write a function).

Here is a sample of the output. Please make up your own hash array.

Here are the keys of the hash
BugsMorkTweetyBillLaverneRalph

Here are the values of the hash
ElmerMindySylvesterBuddyShirleyNorton

Here are the name, value pairs
Bugs Elmer
Mork Mindy
Tweety Sylvester
Bill Buddy
Laverne Shirley
Ralph Norton

Here are the name, value pairs with three pairs deleted
Mork Mindy
Laverne Shirley
Ralph Norton

Where is Perl????

On solix the command for Perl will be
#!/home/sol2/bin/perl

On mongoose the command for Perl will be
#!/usr/local/bin/perl

Creating and Running the program

Use either the pico editor or the emacs editor to type in your program
Exit back to the shell, and change the mode of your file to 700
chmod 700 hw2.pl
Now, to run the program, just type its name at the prompt. Include ./ before to be sure the operating system can find it.
./hw2.pl
If there are errors, then reopen the editor and make the corrections, then try to run it again. However, you only have to do the chmod command once.

Handing it in

Be sure that your name, section, and oath attesting that you did the work on your own are included at the start of your file as comments.
To create a listing, use the script command from solix or mongoose.
1. Enter the command
  script
2. Use the cat command to display the file
  cat hw1.pl
3. Run the program several times with different input
4. Repeat steps 2 and 3 for each program.
5. Type exit to end the script session
Print out the typescript file using lpr. Hand in the printout.
Upload a copy of each script via the web: Submitting Homework Online from mongoose or solix