#!/usr/bin/perl
use warnings;
print"\n Enter the Filename (x.txt) with Data in List context: ";
$filename = <STDIN>;
chomp$filename;
# open the file, or exit
 unless ( open(FILE, $filename) ) {
 print "Cannot open file \"$filename\"\n\n";
 exit;
 } 
 $list = <FILE>; 
print"\n List= $list\n";
@array=split('',$list); # To convert scalar to array
print"\n Array From the List= @array\n";
$N_elements=@array;     # To count number of elements in array 
print"\n Number of Elements= $N_elements\n";
# Sum of all elements in array:
$sum=0;
$sum=eval join '+',@array;
# Mean of the list:  
$mean=$sum/$N_elements;    # Line 21  
print"\n Mean of the list= $mean\n";
exit;

##</code><code>##

Enter the Filename (x.txt) with Data in List context: x.txt

 List= (10,12,14,16,18);

 Array From the List= ( 1 0 , 1 2 , 1 4 , 1 6 , 1 8 ) ;

 Number= 17
Use of uninitialized value $sum in division (/) at C:\Users\x\Desktop\mean.pl
 line 21, <FILE> line 1.

 Mean of the list= 0

##</code><code>##

Enter the Filename (x.txt) with Data in List context: x.txt

 List= (10,12,14,16,18);

 Array From the List= ???

 Number of Elements= 5

 Mean of the list= 14