Beginning Perl

APPENDIX

Answers to Exercises

CHAPTER 3 ANSWERS TO EXERCISES

Exercise 1 Solution

The major difference between strict and warnings is that strict prevents your program from running when it encounters some unsafe code, such as using an undeclared variable.

In contrast, warnings do not prevent your program from running but instead emit “warnings” when your code exhibits behavior that may be problematic, such as when you attempt to use an uninitialized variable or try to add a number to a string.

Exercise 2 Solution

The following is an example (code file exercise_3_2a_array.pl) to create an array with the values Andrew, Andy, and Kaufman and writing a program that prints Andrew "Andy" Kaufman:

use strict;
use warnings;
use diagnostics;
 
my @name = qw(Andrew Andy Kaufman);
print qq{$name[0] "$name[1]" $name[2]\n};

Another way to accomplish this is as follows (code file exercise_3_2b_array.pl):

use strict;
use warnings;
use diagnostics;
 
my @name = ('Andrew', 'Andy', 'Kaufman');
my ( $first, $nick, $last ) = @name;
print qq{$first "$nick" $last\n};

Exercise 3 Solution

The following code (code file exercise_3_3_fruit.pl) is an example of how to create a hash with the keys being names of fruits and the values being their normal color, and then printing every key/value pair as a separate line similar to bananas are yellow:

use strict; use warnings; use diagnostics; my %color_for = ( bananas => 'yellow', apples => 'red', oranges => 'orange', ); for my $fruit (keys %color_for) { my $color = ...