在最常见的情况下，chop可以用substr来表示：
$last_char = chop($var);
$last_char = substr($var, -1, 1, ""); # 同上
再来看下面的完整的例子：
#!/usr/bin/perl
$string1 = "This is test";
$retval = chop( $string1 );
print " Choped String is : $string1n";
print " Character removed : $retvaln";
结果：
Choped String is : This is tes
Number of characters removed : t
