examples/scalars/string_number.pl
#!/usr/bin/perl
use strict;
use warnings;

print 3   . "", "\n";
print 3.1 . "", "\n";

print "3"   + 0, "\n";
print "3.1" + 0, "\n";

print "3x"  + 0, "\n"; # warning: Argument "3x" isn't numeric in addition (+)
print "3\n" + 0, "\n"; 
print "3x7" + 0, "\n"; # warning: Argument "3x7" isn't numeric in addition (+)

print ""    + 0, "\n"; # warning: Argument "" isn't numeric in addition (+)
print "z"   + 0, "\n"; # warning: Argument "z" isn't numeric in addition (+)
print "z7"  + 0, "\n"; # warning: Argument "z7" isn't numeric in addition (+)