perl 语言学习——从C/C++到perl

use strict;
use warnings;
#数值比较大小和字符串比较大小
my $str1="1 -the first str";
my $str2="1 - the second str";
if($str1==$str2)
{
print "numerically equal\n";
}
if($str1 eq $str2)
{
print "stringwise equal\n" ;
}
print "a.b"."haha"

有用的测试样例：

use strict;
use warnings;
my $x=1;
if($x)
{
print "x:yes\n";
}
my $y=0;
if($y)
{
print "y:yes\n";
}
my $z=0.0;
if($z)
{
print "z:yes\n";
}
my $a="0";
if($a)
{
print "a:yes\n";
}
my $b='00';
if($b)
{
print "b:\yes\n" ;
}
my $c= "0.0";
if($c)
{
print "c:yes\n";
}
my $d="";
if($d)
{
print "d:yes\n";
}
my $e=" ";
if($e)
{
print "e:yes\n"
}
my $g="0";
if($g==$c)
{
print "numerically equal" ;
}
if($g eq $c)
{
print "string-wise equal";
}