# Always start your scripts with use strict and use warnings.
use strict;
use warnings;

$| = 1;    # autoflush your print statements

# This subroutine slurps a text file into a string.
# Note the use of a lexical file handle and three-argument open
# and localization of the $/ global variable.
# Note that the lexical $fh is automatically closed at end
# of scope, i.e. when the subroutine exits.
sub slurp_file
{
   my $file = shift;
   open( my $fh, '<', $file ) or die "error: open '$file': $!";
   local $/ = undef;
   return <$fh>;
}

# Note: you can use forward slashes on Windows (saves you escaping backslashes).
my $file = 'c:/Users/yashu/Desktop/SNLP/EX4/test.txt';

my $mytext = slurp_file($file);
$mytext = lc $mytext;
# $mytext =~ s/[^a-z|]/ /g;   # your original replaces with space
$mytext =~ s/[^a-z|]//g;      # this deletes [^a-z|] instead
my @wordarray = split //, $mytext;

my $iter = 0;
print "@wordarray\n";
# Note with a for loop you don't need the ugly array indexes.
for my $wordchar (@wordarray)
{
   while (1)
   {
      print " \n Enter the character then press ENTER : ";
      my $char = <STDIN>;
      chomp $char;
      if ( length($char) != 1 )
      {
         print "you must enter exactly one character (not $char)\n";
         next;
      }
      print "\n inputted character is : $char ";
      if ( $char eq $wordchar )
      { 
         print "Correct !!";
         last;
      }  
      print "\n Wrong please try again ";
      $iter++;
      print "\n Number of attempts : $iter ";
   }
}
print "\nNumber of failed attempts: $iter\n";