输入字符串，按照用户指定长度进行缩进

#!/usr/bin/perl

# Author:  lyg

# Date & Time: 2011-08-26 18:31:02

# Description: 

 

print "pls input string:\n";

chomp(@string=);

print "pls input string's length:\n";

chomp($length=);

if ( $length !~ /[0-9]/) {

        print "string's length must be a number!\n";

}

print "123456789012345678901234567890\n";

        foreach (@string)       {

                printf "%" . $length . "s\n",$_;

        }

 

 

 

重点在于if ( $length !~ /[0-9]/)

判断$length  是否为一个整数