Shell Programming and Scripting

if (allequal($hpver, $hlver, $hrver)) {
 print "They're all equal!\n"
} else {
 print "They're not all equal!\n";
}

sub allequal {
 my $first = shift;
 for (@_) {
  return 0 unless $first == $_;
 }
 return 1;
}

${variable:-defaultvalue}

#!/usr/bin/perl
$a = 3;
$b ;
$c = 3;

  if ((defined $a) && (!defined $b) && (!defined $c)) {};

  if ((defined $a) && (defined $b) && (defined $c)) { 
     print "all defined\n";
      if (!allequal($a, $b, $c)) { 
       print "They're not all equal!\n";
      }
  }

  if ((defined $a) && (defined $b) && (!defined $c)) {
     print "only \$a $a and \$b $b are defined. But not \$c $c\n";
      if (!allequal($a, $b)) {
       print "They're not all equal!\n";
      }
  }

  if ((defined $a) && (!defined $b) && (defined $c)) {
     print "only \$a $a and \$c $c are defined. But not \$b $b\n";
      if (!allequal($a, $c)) {
       print "They're not all equal!\n";
      }
  }


sub allequal {
 my $first = shift;
 for (@_) {
  return 0 unless $first == $_;
 }
 return 1;
}

#!/usr/bin/perl
#
#
#

use strict;
use diagnostics;

# set vars
my $p = "1676:790";
my $l = "1763:890";
my $r = "1676:790";
my $retval = 0;

# test to see if all the strings have a value
if((&checkVal($p, $l, $r)) eq 1) {
    print "They're not equal!\n";
} else {
    print "They're equal!\n";
}

# subroutine to perform the test
sub checkVal {
    # read values into an array
    # this will capture even the
    # empty values
    my @values = @_;
    foreach(@values) {
        # test if a value is empty and set
        # the return value to 1
        if($_ eq "") {
            $retval = 1;
        }
    }
    return $retval;
}

$
$ cat -n test_equality.pl
     1  #!perl -w
     2  use strict;
     3
     4  # ========================
     5  # Subroutines section
     6  # ========================
     7
     8  sub allequal {
     9      my ($p, $l, $r) = @_;                                 # Assign to local variables
    10
    11      my $all = join("", @_);                               # Join them all
    12                                                            # $all cannot be "" since at least one var is defined
    13      if ($p eq $all or $l eq $all or $r eq $all) {         # If any two are NULLs then die
    14          die "Only one var is defined; nothing to do!"
    15      }
    16
    17      if ("" eq $p // "") {                                 # If only one is defined then return
    18          return $l eq $r;                                  # the result of comparison of the other two
    19      } elsif ("" eq $l // "") {
    20          return $p eq $r;
    21      } elsif ("" eq $r // "") {
    22          return $p eq $l;
    23      }
    24
    25      return $p eq $l && $l eq $r && $r eq $p;              # All are non NULLs, hence compare them all
    26  }
    27
    28  # ========================
    29  # Main section
    30  # ========================
    31  print "Enter value of \$hpver : ";
    32  chomp(my $hpver = <STDIN>);
    33
    34  print "Enter value of \$hlver : ";
    35  chomp(my $hlver = <STDIN>);
    36
    37  print "Enter value of \$hrver : ";
    38  chomp(my $hrver = <STDIN>);
    39
    40  print "You entered: (\$hpver = [$hpver], \$hlver = [$hlver], \$hrver = [$hrver])\n";
    41
    42  if (allequal($hpver, $hlver, $hrver)) {
    43      print "They're all equal!\n"
    44  } else {
    45      print "They're not all equal!\n";
    46  }
    47
 
$ perl test_equality.pl
Enter value of $hpver : 1676:790
Enter value of $hlver : 1676:790
Enter value of $hrver : 1676:790
You entered: ($hpver = [1676:790], $hlver = [1676:790], $hrver = [1676:790])
They're all equal!
 
$ perl test_equality.pl
Enter value of $hpver : 1676:790
Enter value of $hlver : 1763:890
Enter value of $hrver : 1676:790
You entered: ($hpver = [1676:790], $hlver = [1763:890], $hrver = [1676:790])
They're not all equal!
 
$ perl test_equality.pl
Enter value of $hpver : 1676:790
Enter value of $hlver :
Enter value of $hrver :
You entered: ($hpver = [1676:790], $hlver = [], $hrver = [])
Only one var is defined; nothing to do! at test_equality.pl line 14, <STDIN> line 3.
 
$ perl test_equality.pl
Enter value of $hpver : 1676:790
Enter value of $hlver : 1676:790
Enter value of $hrver :
You entered: ($hpver = [1676:790], $hlver = [1676:790], $hrver = [])
They're all equal!
 
$ perl test_equality.pl
Enter value of $hpver :
Enter value of $hlver : 1676:790
Enter value of $hrver : 1763:890
You entered: ($hpver = [], $hlver = [1676:790], $hrver = [1763:890])
They're not all equal!
 
$
$