CGS3993, Spring 1999, Perl Assignment 1

Due Tuesday 2/9 at the start of class

Read chapter 2 of the Perl book. Write a PERL script that will do the following

• 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 program that does the following

• Reads a list of numbers (on separate lines) until the user enters -1.
• Prints the list of numbers entered by the user. Do not use a loop for this part.
• Prints the list of numbers entered by the user in reverse order. Do not use a loop for this part.
• Prints the largest number that the user entered. You will need a loop for this. Do not use the sort function.
• Prints the smallest number that the user entered. You will need a loop for this. Do not use the sort function.
• Prints the average of the numbers entered.
• Prints 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.

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.
  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.