Hi Perlmonks

I am a beginner in perl programming. I have written the following perl script  count.pl to count the difference between the total number of letters between two sentences, in a set of sentences. I have used a do-until loop to insert a new sentence each time and finally to quit the loop by typing "quit". Then my interest is to store each new sentence as a scalar variable in an array so that I can do some further operations between the elements of the array (line number 34 marked).I donot know the code to be used at line number 34 and 38. Can any one help me? I have given below three input files namely s1.txt, s2.txt and s3.txt, each with a sentence and the results of cmd screen.

#!/usr/bin/perl
# To calculate the difference of total letters between pairs of senten
+ces 
 use strict;
 use warnings;
# An array, initialized to the empty list, to store the new sentence i
+n 
 my @all_sentences=();     # Line 6 
# Using a do-until loop to insert a new sentence 
 my $input;
 do { 
# Input a sentence
print "\n\n Please type the filename(.txt): "; # Line 11
 my $filename= <STDIN>;
 chomp $filename;
# open the file or exit
 unless ( open(FILE, $filename) ) {
 print "Cannot open file \"$filename\"\n\n";  # Line 16  
 exit;
 } 
 my $sentence=<FILE>;
 close FILE;
# To remove white space & fullstop            # Line 21 
 $sentence=~ s/\s//g;
 $sentence=~ s/\.//g;
print"\n Sentence: $sentence\n";
# To count number of total letters
 my $total_letters=0; 
 $total_letters=length($sentence);
 print"\n Total letters in the sentence= $total_letters\n";# Line 25 2
+8  
print"\n Type \"quit\" to quit or press ENTER to continue: "; 
 $input=<STDIN>;
 }
 until ($input=~ /^\s*q/i);                  # Line Line 32  
# To store all sentences as elements in the array for further comparis
+ons 
 @all_sentences=(my $sentence);                 # Line 34  
# To find the difference of letters between  pairs of sentences i.e.
# sentence1 & sentence2, sentence2 & sentence3,sentence1 & sentence3 e
+tc. 
# Find the difference of letters between any two sentences   # Line 37
+  
 my $diff_letters="code?????";             # Line 38    
print"\n Difference of letters between sentence1 & sentence2=my $diff_
+letters\n
 Difference of letters between sentence2 & sentence3=my $diff_letters\
+n
 Difference of letters between sentence1 & sentence3=my $diff_letters\
+n\n\n";
# Print to a text file:
 my $output="Result .txt";      # Line 42    
 open (my $fh,">",$output) or die"Can't open file '$output'.\n";# Line
+ 43   
print $fh "\n Difference of letters between sentence1 & sentence2=$dif
+f_letters\n"; 
print $fh "\n Difference of letters between sentence2 & sentence3=$dif
+f_letters\n"; 
print $fh "\n Difference of letters between sentence1 & sentence3=$dif
+f_letters\n\n"; 
 close $output;                 # Line 47    
# exit the program 
exit;
[download]

Input file s1.txt:

Input file s2.txt:

Input file s3.txt:

Output in cmd screen appears as follows as I could not write the code at line 38 & 34:

Microsoft Windows [Version 6.1.7600]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\x>cd desktop

C:\Users\x\Desktop>new2.pl


 Please type the filename(.txt): s1.txt

 Sentence: Ihaveadog

 Total letters in the sentence= 9

 Type "quit" to quit or press ENTER to continue:


 Please type the filename(.txt): s2.txt

 Sentence: Mostkidslikecomputergames

 Total letters in the sentence= 25

 Type "quit" to quit or press ENTER to continue:


 Please type the filename(.txt): s3.txt

 Sentence: ButIliketoplaywithmydog

 Total letters in the sentence= 23

 Type "quit" to quit or press ENTER to continue: quit

 Difference of letters between sentence1 & sentence2=my code?????

 Difference of letters between sentence2 & sentence3=my code?????

 Difference of letters between sentence1 & sentence3=my code?????


C:\Users\x\Desktop>
[download]