Perl语言入门-第五章-输入与输出-习题

1. 习题

   

2. 代码与输出

cat_reverse.pl

 1 #-----------------------------------------------------------#
 2 # Source: Learning Perl, chapter5, exercise-1
 3 # Date:   2012-01-15
 4 # Author: xiaodongrush
 5 #-----------------------------------------------------------#
 6 use 5.010;
 7 while(<>) { chomp; unshift @array,$_; }
 8 foreach(@array) { say $_; }
 9 <STDIN>
10 # @_表示子程序的参数列表，$_是Perl的老地方，容易混淆

printf_example.pl

 1 #-----------------------------------------------------------#
 2 # Source: Learning Perl, chapter5, exercise-2
 3 # Date:   2012-01-15
 4 # Author: xiaodongrush
 5 #-----------------------------------------------------------#
 6 use 5.010;
 7 say "Input several str! (Use Control+Z to Stop Input).";
 8 while(<>) { chomp; push @strs,$_; }
 9 say "1234567890" x 4;
10 foreach(@strs) { printf "%20s\n",$_; }
11 <STDIN>

printf_example_2.pl

 1 #-----------------------------------------------------------#
 2 # Source: Learning Perl, chapter5, exercise-3
 3 # Date:   2012-01-15
 4 # Author: xiaodongrush
 5 #-----------------------------------------------------------#
 6 use 5.010;
 7 say "Input several str! (Use Control+Z to Stop Input).";
 8 while(<>) { chomp; push @strs,$_; }
 9 print "The Width of the Rule Line Width = "; $width = <STDIN>;
10 print "1234567890" x ($width/10); 
11 foreach(1..9) { if($_ <= ($width%10)) { print $_; } } say;
12 foreach(@strs) { printf "%20s\n",$_; }
13 <STDIN>

3. 文件

    /Files/pangxiaodong/LearningPerl/ch5-answer.rar