#!/usr/bin/perl -w
# ex2_7.pl
# solution to Exercise 2.7 from Deitel
# @Natasha Khuri

print "Please, enter the first number: ";
$num1 = <STDIN>;
chomp($num1);

print "Please, enter the second number: ";
$num2 = <STDIN>;
chomp($num2);

$sum = $num1 + $num2;
$product = $num1 * $num2;
$diff = $num1 - $num2;
$quot = $num1/$num2;

print "The sum of two numbers is ", $sum, "\n";
print "The product of two numbers is ", $product, "\n";
print "The difference of two numbers is ", $diff, "\n";
print "The quotient of two numbers is ", $quot, "\n";

exit;
------------------------------------------------------
#!/usr/bin/perl -w
# ex2_9.pl
# @Natasha Khuri

print "Input a five-digit number: ";
$number = <STDIN>;
chomp($number);
$fifth = chop($number);
$fourth = chop($number);
$third = chop($number);
$second = chop($number);
$first = chop($number);

print $first, "\n";
print $second x 2, "\n";
print $third x 3, "\n";
print $fourth x 4, "\n";
print $fifth x 5, "\n";

exit;
---------------------------------------
#! /usr/bin/perl -w
# ex2_11.pl
# @Natasha Khuri

print "Enter the first string: ";
$string1 = <STDIN>;
chomp($string1);

print "Enter the second string: ";
$string2 = <STDIN>;
chomp($string2);

if ($string1 lt $string2)
{
   print "$string1 $string2\n";
}

if ($string2 lt $string1)
{
   print "$string2 $string1\n";
}

if ($string1 eq $string2)
{
   print "$string1\n$string2\n";
}

exit;
------------------------------------------------------

#!/usr/bin/perl -w
# ex2_12.pl
# Solution to Exercise 2.12 from Deitel
# @Natasha Khuri

print "Enter a number between 1 and 30: ";
$number1 = <STDIN>;
chomp($number1);

print "Enter a number between 1 and 30: ";
$number2 = <STDIN>;
chomp($number2);

print "Enter a number between 1 and 30: ";
$number3 = <STDIN>;
chomp($number3);

print "Enter a number between 1 and 30: ";
$number4 = <STDIN>;
chomp($number4);

print "Enter a number between 1 and 30: ";
$number5 = <STDIN>;
chomp($number5);

print "*" x $number1, "\n";
print "*" x $number2, "\n";
print "*" x $number3, "\n";
print "*" x $number4, "\n";
print "*" x $number5, "\n";

exit;
-------------------------------------------
#! /usr/bin/perl -w
# ex3_10.pl
# Solution to Exercise 3.10 from Deitel
# @Natasha Khuri

$total_miles = 0;
$total_gallons = 0;

print "Enter the gallons used (-1 to end): ";
$gallons = <STDIN>;
chomp ($gallons);

while ($gallons != -1)
{
   print "Enter the miles driven: ";
   $miles = <STDIN>;
   chomp($miles);

   print "The miles / gallon for this tank was ", $miles/$gallons, "\n";

   $total_gallons += $gallons;
   $total_miles += $miles;

   print "Enter the gallons used (-1 to end): ";
   $gallons = <STDIN>;
   chomp ($gallons);
}

unless ($total_gallons == 0)
{
   print "The overall average miles / gallon was: ", 
        $total_miles / $total_gallons, "\n";
}

exit;
-----------------------------------------------------------
#!/usr/local/bin/perl   -w
# ex3_13.pl
# problem 3.13, page 93
# converting a binary number to decimal
# @Deitel

print( "Input a binary number: " );
chomp( $binary = <STDIN> );

$bit = 0;
$decimal = 0;
$x = $binary / ( 10 ** $bit );

while ( $x >= 1 ) {
   $digit = $x % 10;
   $decimal += $digit * 2 ** $bit;
   $bit++;
   $x = $binary / ( 10 ** $bit );
}

print( "The decimal representation for $binary is $decimal.\n" );

exit;
-------------------------------------------------------------------
#!/usr/local/bin/perl -w
# ex3_14a.pl
# problem 3.14a, page 93
# computing the factorial of a number
#@Deitel

print( "Enter a number: " );
chomp( $number = <STDIN> );

$factorial = 1;

$i = $number;

while ( $i > 0 ) {
   $factorial *= $i;
   $i--;
}

print( "$number! = $factorial\n" );

exit;
----------------------------------------------------------------
#!/usr/local/bin/perl -w
#ex4_5.pl
#Deitel problem 4.5 p. 134
#@Natasha Khuri

@array = (1 .. 9);
%hash = (
        1 => 'one',
        2 => 'two',
        3 => 'three',
        4 => 'four',
        5 => 'five',
        6 => 'six',
        7 => 'seven',
        8 => 'eight',
        9 => 'nine');


print "\@array contents are @array\n";
print "\%hash contents are\n";

while ( ( $key, $value ) = each (%hash))
{
   print "$key => $value\n";
}
exit;
--------------------------------------------------------------
#!/usr/local/bin/perl -w
#ex4_6.pl
#Deitel Exercise 4.6 p. 134
#@Natasha Khuri

@array = (1 .. 10);
%hash = @array;

@keys = keys (%hash);

print "\%hash keys are @keys\n";

@values = values (%hash);
print "\%hash values are @values\n";
 
exit;
-----------------------------------------------------
#!/usr/loca/bin/perl -w
#Deitel exercise 4.7 p. 134
#@Natasha Khuri

@deck = (1 .. 52);   #create the deck of cards

print "The deck of cards is\n";
print "@deck\n";
print "\nShuffling.............\n\n";

@first_half = @deck[0 .. 25];   #slice half of @deck array
@second_half = @deck[26 .. 51]; #slice the remainder of @deck

@deck = ();                     #empty @deck

#longer version
while( @first_half )
{
   $x = shift(@first_half);     #retrieve first element of @first_half
   push(@deck, $x);             #add it to end of @deck

   $y = shift(@second_half);    #retrieve first element of @second_half
   push(@deck, $y);             #add it to end of @deck
}

#shorter version
#while ( @first_half ) {
#   push( @deck, shift @first_half );
#   push( @deck, shift @second_half );
#}


print "The deck of cards after shuffling is\n";
print "@deck\n";
exit;
----------------------------------------------------------
#!/usr/local/bin/perl -w
#ex4_8.pl
#Deitel Exercise 4.8 p.134
#@Natasha Khuri

@array = (10 .. 20);

#note array is sorted in decreasing order
@sorted = sort {$b <=> $a} @array;

$sum = 0;
$num_elements = scalar (@array);

while (@array)
{
  $sum += pop(@array);
} 

print "The size of the array is $num_elements\n";
$average = sprintf("%.2f", $sum/$num_elements);
print "The sum of array elements is $sum\n";
print "The average of array elements is $average\n";
print "The five largest elements are: ";

$#sorted = 4; # shortened the array to contain 5 elements
print "@sorted\n";
exit;
--------------------------------------------------------
#!/usr/local/bin/perl -w
#ex4_9.pl
#solution to problem 4.9 p.134
#@Natasha Khuri

#@array = (1, 10.2, 'stuff', 'peanut', 1, 2, 15.4, 2, 4.46, 'peanut');
# or for the quiz try the following array:
#@array = ('a' .. 'z', 'a', 'c');

while(@array)
{
   #note that since the order in which
   #elements are removed does not matter
   #it is better to use pop

   $element = shift(@array);
   if (exists ($hash{$element} ))
   {
      print "$element is duplicated\n";
   }
   else
   {
       $hash{$element} = 1;
   }
}

exit;
----------------------------------------------------------------
#!/usr/bin/perl -w
#ex5_6.pl
#solution to Exercise 5.6 p. 169
#@Natasha Khuri

print "Enter a non-negative integer: ";
$number = <STDIN>;
chomp ($number);

if($number < 0)
{
   print "Invalid integer\n";
   print "Enter a non-negative integer: ";
   $number = <STDIN>;
   chomp ($number);
}

if($number == 0)
{
   $factorial = 1;
}
else
{
   $factorial = 1;
   foreach $x (1 .. $number)
   {
        $factorial *= $x;
   }
}

print "$number! is $factorial\n";
exit;
-------------------------------------------------------------
#!/usr/local/bin/perl -w
#ex5_9.pl
#Solution to Exercise 5.9 p. 169
#@Natasha Khuri

for ( $i = 0; $i < 10; $i++ ) 
{
   print( "Enter a number: " );
   chomp( $number = <STDIN> );
   push( @array, $number );
}

print( "\n" );

#part a: foreach structure
print "Using foreach structure:\n";
foreach $element (@array)
{
   $square = $element ** 2;
   print "$square\n" if ( ($square >= 100) && ($square <= 200));
}

#part b: grep function
print "Using grep and map functions:\n";
@squared_numbers = map ($_ ** 2, @array);
@result = grep ( (($_  >=100) && ($_ <= 200)), @squared_numbers); 

#shorter version
@results = grep ( $_ >= 100 && $_ <= 200, map ( $_ ** 2, @array ) );

$" = "\n";              
#reset the special variable to output each element
#of @result on a new line 
print "@result\n";
exit;
--------------------------------------------------------------------
#! /usr/bin/perl -w
# ex5_10.pl
# Solution to Exercise 5.10 from Deitel
# @Natasha Khuri

$total_miles = 0;
$total_gallons = 0;

for ($i=0; ;++$i)
{
   print "Enter the gallons used (-1 to end): ";
   $gallons = <STDIN>;
   chomp ($gallons);

   last if ($gallons == -1);

    print "Enter the miles driven: ";
    $miles = <STDIN>;
    chomp($miles);
    
    redo if ($gallons < 0 or $miles < 0);

    print "The miles / gallon for this tank was ";
    print $miles/$gallons, "\n\n";

    $total_gallons += $gallons;
    $total_miles += $miles;
}       

unless ($i == 0)
{
   print ("The overall average miles / gallon was: ");
   printf ("%.2f\n", $total_miles / $total_gallons);
   print ("The average miles / tank was: ");
   printf ("%.2f\n", $total_miles / $i);
   print ("The average gallons per fillup was: ");
   printf ("%.2f\n", $total_gallons / $i);
}

exit;
----------------------------------------------------------------------
#!/usr/bin/perl -w
# ex6_4.pl
#solution to exercise 6.4 p. 175
#@Natasha Khuri

num_arguments();
num_arguments(1);
num_arguments("one", "two", "three");

sub num_arguments
{
  print "Number of arguments passed: ";
  print scalar (@_), "\n";
}
----------------------------------------------------------------
#!/usr/bin/perl -w
# ex6_6.pl
#solution to exercise 6.6 p. 215
#@Natasha Khuri

%my_hash = roll(6000);
print "Outcome\tFrequency\n";

while ( ($key, $value)= each(%my_hash))
{
   print "$key\t$value\n";
}

sub roll
{
  $times = shift(@_);

  srand(time|$$); # not really needed
  foreach ( 1 .. $times)
  {
    $side = 1 + int (rand(6));
    ++ $result_hash{$side};
  }
  return %result_hash;
}

exit;
-----------------------------------------------------------
#!/usr/local/bin/perl -w
#ex6_7.pl
#solution to Exercise 6.7
# @Deitel

use strict;

my @numbers = ( 1, 7, 3, 8, 4, 2, 45, 53, 1, 3 );

print( "Maximum recursively is: ", 
       recursiveMaximum( @numbers ), "\n" );
print( "Maximum iteratively is: ", 
       iterativeMaximum( @numbers ), "\n" );

sub recursiveMaximum
{
   my @numbers = @_;

   if ( @numbers == 1 ) {
      return shift( @numbers );
   }
   else {
      my $first = shift( @numbers );
      my $max = recursiveMaximum( @numbers );
      return ( $first > $max ) ? $first : $max;
   }
}

sub iterativeMaximum
{
   my @numbers = @_;
   my $max = shift( @numbers );

   foreach ( @numbers ) {
      $max = ( $max > $_ ) ? $max : $_;
   }

   return $max;
}

exit;
-----------------------------------------------------------
#!/usr/bin/perl
# Ex. 6.8: HTMLpackage.pm
# Package of subroutines for creating HTML markup.

package HTMLPackage;

our $title = '';

sub startDocument {
   return "<html><head><title>$title</title></head><body>\n";
}

sub createParagraph {
   return "<p>@_</p>\n";
}

sub createHyperlink {
   return "<a href= \"$_[ 1 ]\">$_[ 0 ]</a>\n";
}

sub endDocument{
   return "</body></html>\n";
}

return 1;
-----------------------------------------------------------
#! /usr/local/bin/perl  -w
# problem 6.9, page 215
# Demonstrating the different ways 
# of calling localtime.
#@Natasha Khuri
use strict;

my $scalar = get_time();
my @array = get_time();
print( "Calling localtime in a scalar context:\n" );
print( "$scalar", "\n\n" );
print( "Calling localtime in a list context:\n" );
print( "@array", "\n" );

sub get_time
{
   if (wantarray())
   {
        return localtime();
   }    
   else
   {
        return localtime();
   }
}

exit;
-----------------------------------------
#!C:\Perl\bin\perl.exe -w
#ex7_7.cgi
#solution to Exercise 7.7 p. 250
#Using CGI.pm to determine the properties of a triangle.
#@Deitel

use warnings;
use strict;
use CGI qw( :standard );

print( header() );
print( start_html( "Triangles" ) );

my $hypotenuse = param( "Hypotenuse" );
my $shorter = param( "Short" );
my $longer = param( "Long" );

if ( $hypotenuse && $shorter && $longer ) {

   if ( $hypotenuse < $shorter || $hypotenuse < $longer 
        || $longer < $shorter ) {
      print( "Please re-enter the three sides ",
             "in the correct places: " );
      ourform();
   }
   elsif ( $hypotenuse >= $shorter + $longer ) {
      print( "Those three sides do not make a triangle, ",
             "please reenter: " );
      ourform();
   }
   else {
      print( "The triangle with the sides $hypotenuse, ",
             "$shorter, and $longer is " );

      if ( $hypotenuse == $shorter && $hypotenuse == $longer ) {
         print( "an equilateral triangle." );
      }
      else {

         if ( $hypotenuse == $longer || $shorter == $longer ) {
            print( "an isocolese " );

            if ( $hypotenuse ** 2 == $longer ** 2 + 
                                     $shorter ** 2 ) {
               print( "and a right triangle." );
            }
            else {
               print( "triangle." );
            }
         }
         elsif ( $hypotenuse ** 2 == $longer ** 2 +
                                     $shorter ** 2 ) {
            print( "a right triangle." );
         }
         else {
            print( "not special." );
         }
      }
   }
}
else {
   print( "Please enter the three sides of a triangle:\n" );
   ourform();
}

print( end_html() );

sub ourform 
{
   print( start_form(),
         "Hypotenuse ", textfield( -name => "Hypotenuse" ),
         br(), "Longer side ", textfield( -name => "Long" ),
         br(), "Shorter side ", textfield( -name => "Short" ),
         br(), submit( "Submit" ),
         end_form() );
}
-------------------------------------------------------------
#!C:\Perl\bin\perl.exe -w
#ex7_8.cgi
#solution to Exercise 7.8 p. 251
#A soothsayer program.
#@Deitel

use warnings;
use strict;
use CGI qw( :standard );

print( header(), start_html( "Soothsayer Program" ) );

if ( param ) {
   my @array = ( "Signs point to yes", "No", "Yes", 
                 "Ask later", "Perhaps not", "Could be", 
                 "No chance", "Never!!!!" );
   
   print( h1( $array[ rand( 8 ) ] ) );
}
else {
   print( h1( "Soothsayer" ), br(),
          p( "Enter your question here: " ), start_form(),
          textfield( -name => "question" ), submit(),
          end_form() );
}

print( end_html() );
----------------------------------------------------------
!/usr/bin/perl
# Exercise 8.5: Ex08_05.pl
# Convert all words to uppercase.
# (c) Deitel

use strict;
use warnings;

print( "Enter a string: " );
chomp ( my $string = <STDIN> );

print( capitalize( $string ) );

sub capitalize
{
   my $string = shift();
   $string =~ s/\b(\w)/\u$1/g;
   return $string;
}
------------------------------------------------------------
#!/usr/bin/perl
# Exercise 8.6: Ex08_06.pl
# A regular expression to count digits, whitespace and words.
# copyright Deitel

use strict;
use warnings;

print( "Enter a string: " );
chomp ( my $string = <STDIN> );

my $digits = 0;
$digits++ while ( $string =~ /\d/g );

my $whitespace = 0;
$whitespace++ while ( $string =~ /\s/g );

my $words = 0;
$words++ while ( $string =~ /\b/g );
$words /= 2;

print( "It has $digits digits, $whitespace whitespace ",
       "and $words words.\n" );
--------------------------------------------------------------
#!/usr/bin/perl
# Exercise 8.7: Ex08_07.pl
# Searches for URL's in HTML.

use strict;
use warnings;

searchURL ( "\"http://www.yahoo.com\"" );

searchURL ( "<a href=\"http://www.prenhall.com/deitel\" 
target=\"_blank\">" );

searchURL ( "<input type=\"image\" 
src=\"http://g.akamai.net/graphics.boston.com/images/go.gif\" 
alt=\"Go!\" border=\"0\"></form></td><td valign=top>
<a href=\"/globe/\"><IMG WIDTH=\"99\" HEIGHT=\"78\" 
SRC=\"http://g.akamai.net/graphics.boston.com/banners/globe.gif\" 
alt=\"News\" border=\"0\"></a></td></tr><tr><td width=600 
colspan=3><IMG WIDTH=600 HEIGHT=22 SRC=\"http://date.boston.com/\" 
alt=\"Today\" border=0></td></tr></table>" );

sub searchURL
{
   my $string = shift();

   while ( $string =~ m|(?<=")(http://[^"]+)|g ) {
      print( "URL:  $1\n" );
   }
}

###########################################################################
#  (C) Copyright 2001 by Deitel & Associates, Inc. and Prentice Hall.     #
#  All Rights Reserved.                                                   #
#                                                                         #
#  DISCLAIMER: The authors and publisher of this book have used their     #
#  best efforts in preparing the book. These efforts include the          #
#  development, research, and testing of the theories and programs        #
#  to determine their effectiveness. The authors and publisher make       #
#  no warranty of any kind, expressed or implied, with regard to these    #
#  programs or to the documentation contained in these books. The authors #
#  and publisher shall not be liable in any event for incidental or       #
#  consequential damages in connection with, or arising out of, the       #
#  furnishing, performance, or use of these programs.                     #
###########################################################################
---------------------------------------------------------------------------
#!/usr/bin/perl
# Exercise 8.9: Ex08_09.pl
# Determine how many html tags a certain string has.
# Count for each level of nesting.
# copyright Deitel

use strict;
use warnings;

my $string = "<p><strong>a</strong><a>b</a></p>
<strong>c<italic>d<a>e</a></italic></strong>";

print( "The HTML string is:\n$string\n\n" );

our @counter;
count( $string, 0 );

for ( 0 .. $#counter ) {
   print( "There are $counter[ $_ ] valid level ", $_, 
          " html tags.\n" );
}

sub count
{
   my $string = shift();
   my $level = shift();

   while ( $string =~ m!.*?<([^<]*?)>(.*?)</\1>!g ) {
      $counter[$level]++;
      print( "Tag is \"$1\", contains \"$2\" " );
      print( "at level $level\n" );
      count( $2,$level+1 );
   }
}

###########################################################################
#  (C) Copyright 2001 by Deitel & Associates, Inc. and Prentice Hall.     #
#  All Rights Reserved.                                                   #
#                                                                         #
#  DISCLAIMER: The authors and publisher of this book have used their     #
#  best efforts in preparing the book. These efforts include the          #
#  development, research, and testing of the theories and programs        #
#  to determine their effectiveness. The authors and publisher make       #
#  no warranty of any kind, expressed or implied, with regard to these    #
#  programs or to the documentation contained in these books. The authors #
#  and publisher shall not be liable in any event for incidental or       #
#  consequential damages in connection with, or arising out of, the       #
#  furnishing, performance, or use of these programs.                     #
###########################################################################
--------------------------------------------------------------------------
#!/usr/bin/perl -w
#solution to exercise 13.5 from Deitel
#@Natasha Khuri

use strict;

my %hash = qw(one 1 two 2 three 3 four 4  five 5);
 
#call hashsum with a hash reference and a reference to
#an anonymous array
my $result = &hashsum(\%hash, [qw (one two three) ]);
print $result, "\n";

#call hashsum with a hash reference and an array reference
my @array = ("four", "five");
$result = &hashsum(\%hash, \@array);
print $result, "\n";
   
#create references and call hashsum
my $ref_hash = \%hash;
my $ref_ar = \@array;
$result = &hashsum($ref_hash, $ref_ar);
print $result, "\n";

sub hashsum
{
   my $total = 0;

   my $hash_ref = shift (@_);
   my $array_ref = shift (@_);
   foreach (@$array_ref)
   {
      $total += $$hash_ref{$_} if exists ($$hash_ref{$_});
   }
   return $total;
}
exit;
-----------------------------------------------------------