Input Validation

Validate a numeric value before accepting it.

input_validation.pl

use strict;
use warnings;

my $age = ;
my $status;

if ($age < 0) {
    $status = "invalid";
} elsif ($age < 18) {
    $status = "minor";
} else {
    $status = "adult";
}

print "age=$age\n";
print "status=$status\n";

use strict;
use warnings;

my $age = ;
my $status;

if ($age < 0) {
    $status = "invalid";
} elsif ($age < 18) {
    $status = "minor";
} else {
    $status = "adult";
}

print "age=$age\n";
print "status=$status\n";

use strict;
use warnings;

my $age = ;
my $status;

if ($age < 0) {
    $status = "invalid";
} elsif ($age < 18) {
    $status = "minor";
} else {
    $status = "adult";
}

print "age=$age\n";
print "status=$status\n";

input-validation Validation rejects invalid input before later code depends on it.