There are a few things I would do differently
- I'd put the most of the variables into the loop, restricting the scope to just the places they are used will spare you some grief later.
- You need to test that your regular expression matched, if it doesn't you end up processing the previous record again.
- If you have a student with the surname O'Hara you will fail to process her records.
- $status has the value of the last mark checked, I think you mean to check if any failed
- The use of . to join the strings is ugly, use variable interpolation instead.
Anyway this is my version, it still fails to report marks for Ms. O'Hara but at least you will get a warning, and I have to leave something for you;-) The other change is to not explicitly code the number of tests, this will work if the input file has results of four tests.
#!/net/perl/5.10.0/bin/perl
use strict;
use warnings;
use List::Util qw(sum);
my $input_file = 'marks.txt';
open my $DATA, '<', $input_file or die "Can't open $input_file: $!\n";
while ( my $line = <$DATA> ) {
next if $line =~ /^NAME/;
chomp $line;
if ( $line =~ /^\w+,\w+(?:,\d+)+$/ ) {
my ( $first_name, $last_name, @marks ) = split ',', $line;
my $totalmarks = sum @marks;
my $average = sprintf "%.2f", $totalmarks / @marks;
my $fail = 0;
foreach my $mark (@marks) {
$fail ||= checkfail($mark);
}
if ( !$fail ) {
print "$first_name $last_name\t@marks \t$totalmarks\t$aver
+age\n";
}
else {
print "$first_name $last_name\t@marks \t\n";
}
}
else {
warn "Invalid input: $line\n";
}
}
close $DATA or die "Can't close $input_file: $!\n";
#To check whether the student failed
sub checkfail {
my $marks = shift;
return $marks < 35;
}
john michael 100 50 60 210 70.00
sam shane 50 60 70 180 60.00
tom christo 30 40 50
You may wish to give consideration to using Text::CSV_XS for parsing comma delimited text files.
Update: two small code modifications kindly suggested by moritz.
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