#!/usr/bin/perl
use strict;
my $var1=786;

######################################################################
# Numerical comparison
if($var1 < 786)
{
    print "The value is less than 100.\n";
}

if($var1 >= 786)
{
    print "The value is greater than or equal to 100.\n";
}

if($var1 == 786)
{
    print "The value is equal to 100.\n";
}

######################################################################
# String comparison
my $username="Ali";

if($username lt "N")
{
    print "The username appears in the first half of the alphabet.\n";
}


if($username eq "Ali")
{
    print "Hi Dad!\n";
}
else
{
    print "Hello!\n";
}

if($username eq "Ali")
{
    print "Hi Dad!\n";
}
elsif($username eq "Sadri")
{
    print "Hi Mom!\n";
}
else
{
    print "Hello!\n";
}

######################################################################
# Combining conditions
######################################################################
# Boolean AND
my $temperature=19;

if( ($temperature > 18) && ($temperature < 35) )
{
    print "The weather is fine.\n";
}

# Boolean OR
if( ($temperature < 18) || ($temperature > 35) )
{
    print "The weather isn't fine.\n";
}

# Boolean NOT (negating the condition)
if( !($temperature < 18) )
{
    print "The weather isn't cold.\n";
}

######################################################################
# Symbolic and long form of Boolean expressions
######################################################################
# A combined expression...
my $value=74;

if( ($value > 80) || ( ($value < 75) && ! ($value == 73)) )
{
    print "The value is greater than 80 or less than 75, but is not 73\n";
}

# ...and the equivalent in long form
if( ($value > 80) or ( ($value < 75) and not ($value == 73)) )
{
    print "The value is greater than 80 or less than 75, but is not 73\n";
}