Quiz 2 Solution

CS 29

40 pts., Feb. 27

For each problem, design pseudo-code, flowchart, or a perl program to solve it. If you are stuck on either of the problems let me know and I will suggest alterations to the problem(s) which you may work on for partial credit.

Since I did flowcharts in class, I'll give the perl code here.

1. Count from 2 to 20 by 3's.

   #!/usr/contrib/bin/perl -w
   
   $count = 2;
   
   while ($count <= 20)
   {
       print "$count\n";
       $count = $count + 3;
   }
   
   exit 0;
   

2. Prompt the user to enter a series of numbers, one at a time, from the keyboard. When the user enters the number 0, stop prompting and print the sum of the positive (> 0) numbers which were previously entered. For each negative number (< 0) entered, print the message Don't do that! .

   #!/usr/contrib/bin/perl -w
   
   $sum = 0;
   
   print "Enter a 0 to quit.\n\n";
   
   print "Enter a number: ";
   $data = <STDIN>;
   
   while ($data != 0)
   {
       if ($data > 0)
       {
           $sum = $sum + $data;
       }
       else
       {
           print "Don't do that!\n";
       }
   
       print "Enter a number: ";
       $data = <STDIN>;
   }
   
   print "The sum of the positive numbers is: $sum.\n";
   
   exit 0;