8.15. Count digits

Example 8-10. examples/arrays/count_digits.txt

23 34 9512341
3 34 2452345 5353 67 22
42136357013412
42 5 65 64 

Example 8-11. examples/arrays/count_digits.pl

#!/usr/bin/perl
use strict;
use warnings;

my $filename = shift or die "Usage: $0 filename\n";

my @count;

open(my $fh, "<", $filename)
    or die "Could not open '$filename': $!";

while (my $line = <$fh>) {
	chomp $line;
	my @chars = split "", $line;
	foreach my $c (@chars) {
		if ($c ne " ") {
			$count[$c]++;
		}
	}
}

foreach my $i (0..9) {
	print "$i ", ($count[$i] ? $count[$i] : 0), "\n";
}