use strict;

my @arr;
my $exit = 0;

while ($exit == 0) {
  print "Enter a number: ";
  my $val = <>;
  chomp $val;
  if (grep $_ eq $val,@arr) {
    print "Value already exists.\n";
    $exit++;
  }
  else {
    push @arr,($val);
  }
}
print "Array contains:\n";
foreach my $elem (@arr) {print "$elem\n";}