Functions

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Functions1.pl

#!/usr/bin/env perl
use utf8;
use strict;
use warnings;

sub printHello {
	print "Hello, world!\n";
}

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	printHello();
}

Functions2.pl

#!/usr/bin/env perl
use utf8;
use strict;
use warnings;

sub printHello {
	my ($name) = @_;
	print "Hello, ", $name, "!\n";
}

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	printHello("Fred");
	printHello("Wilma");
	printHello("Barney");
	printHello("Betty");
}

Functions3.pl

#!/usr/bin/env perl
use utf8;
use Utils;
use strict;
use warnings;

sub squared {
	my ($j) = @_;
	return $j * $j;
}

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	for (my $i = 1; $i <= 10; ++$i) {
		print Utils::messageFormat("\{0:d\}^2 = \{1:d\}", $i, squared($i)), "\n";
	}
}

Functions4.pl

#!/usr/bin/env perl
use utf8;
use Utils;
use strict;
use warnings;

sub exponentiation {
	my ($base, $powerArg) = @_;
	my $power = $powerArg;
	my $result = 1;
	while ($power > 0) {
		$result *= $base;
		--$power;
	}
	return $result;
}

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	for (my $b = 1.1; $b < 2.05; $b += 0.1) {
		for (my $p = 2; $p <= 10; ++$p) {
			print Utils::messageFormat("\{0:f\} ^ \{1:d\} = \{2:f\}", $b, $p, exponentiation($b, $p)), "\n";
		}
	}
}

Functions5.pl

#!/usr/bin/env perl
use utf8;
use Utils;
use strict;
use warnings;

sub factorial {
	my ($x) = @_;
	if ($x <= 1) {
		return 1;
	}
	return $x * factorial($x - 1);
}

MAIN:
{
	binmode(STDOUT, ":utf8");
	binmode(STDERR, ":utf8");
	binmode(STDIN, ":utf8");
	for (my $x = 1; $x < 10; ++$x) {
		print Utils::messageFormat("\{0:d\}! = \{1:d\}", $x, factorial($x)), "\n";
	}
}

Lists6.pl

#!/usr/bin/env perl
use utf8;
use Utils;
use strict;
use warnings;

sub reverseList {
	my ($x) = @_;
	my $y = [];
	for (my $i = scalar(@{$x}) - 1; $i >= 0; --$i) {
		push(@{$y}, $x->[$i]);
	}
	return $y;
}

MAIN:
{
	my $names = ["Fred", "Wilma", "Barney", "Betty"];

	foreach my $name (@$names) {
		print "Hello, ", $name, "!\n";
	}

	$names = reverseList($names);
	foreach my $name (@$names) {
		print "Hello, ", $name, "!\n";
	}

	print Utils::listToString($names), "\n";
}

Maps3.pl

#!/usr/bin/env perl
use utf8;
use Utils;
use strict;
use warnings;

sub convertKMtoMiles {
	my ($x) = @_;
	my $y = {};
	foreach my $planet (keys(%$x)) {
		$y->{$planet} = int($x->{$planet} * 0.621371 + 0.5);
	}
	return $y;
}

MAIN:
{
	my $planetDiametersInKM = {
		"Mercury" => 4879,
		"Venus" => 12103,
		"Earth" => 12756,
		"Mars" => 6794,
		"Jupiter" => 142985,
		"Saturn" => 120534,
		"Uranus" => 51115,
		"Neptune" => 49534,
		"Pluto" => 2374,
		"Ceres" => 946,
		"Eris" => 2326,
		"Makemake" => 1430
	};

	my $planetDiametersInMiles = convertKMtoMiles($planetDiametersInKM);
	foreach my $planet (keys(%$planetDiametersInMiles)) {
		print $planet, " has a diameter of ", $planetDiametersInMiles->{$planet}, " miles\n";
	}
}

Tuples3.pl

#!/usr/bin/env perl
use utf8;
use Utils;
use strict;
use warnings;

sub swap {
	my ($x) = @_;
	my $y;
	$y = [$x->[1], $x->[0]];
	return $y;
}

MAIN:
{
	my $pair1 = ["Hello", 5];
	my $pair2;
	$pair2 = swap($pair1);
	print Utils::tupleToString($pair1), " becomes ", Utils::tupleToString($pair2), "\n";
}

Questions

• {{Who's on first?}}
• {{Who's on second?}}
• {{Who's on third?}}

Projects

More ★'s indicate higher difficulty level.

• Alouette Lyrics
• Bingo Lyrics
• 99 Bottles of Beer Lyrics
• Bubble Sort
• Calculate Euler's Number
• Compute π Function
• Compute π (Monte Carlo with Central Limit Theorem)
• Credit Card Validator
• The Farmer in the Dell (Revisited)
• Fibonacci Numbers
• Football Passer Rating (Revisited)
• GCD
• Insertion Sort
• LCG Pseudo-Random Number Generator
• License Plate Generator (Revisited)
• Merge Sort
• Min/Max Functions
• Old MacDonald Lyrics
• Quicksort
• Renard Numbers with Rounding Function
• Roman Numerals
• Sign Function
• Spreadsheet Columns
• Tower of Hanoi
• Twelve Days of Christmas Lyrics

References

• [[Perl Language Reference]]
  
• [[Comprehensive Perl Archive Network (CPAN)]]
• [[Beginning Perl]], Simon Cozens
• [[Perl Monks Tutorials]]