See the following Example

#use strict;
#use warnings;

my $var = "Hello World";
if ($var == "Hello World"){    print "Equal\n"; }
if ($var eq "Hello World"){    print "Strings are Equal\n";}
if ($var == "Hello world"){    print "Equal\n"; }
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Here I didn't use the "use strict" and "use warnings".
so the program give the output
Output:
Equal
Strings are Equal
Equals

if I used the "use strict" and "use warning".
Then the output of the program is (different).
Output
Equal
Strings are Equal
Argument "Hello world" isn't numeric in numeric eq (==) at equal.pl line 21.
Equal


--sugumar--