花括号的使用 printf %${width}s , 否则会 去找 $widths

花括号的使用  printf %${width}s , 否则会 去找  $widths

  1 #! /usr/bin/perl
  2 use strict;
  3 use warnings;
  4
  5 =head1
  6 print " ----------------------------------ch_5_Q1_-------------------------- ";
  7 #print reverse <>;
  8 print " ----------------------------------_-------------------------- ";
  9 select STDIN;
 10 my @single_quotation = <>;
 11 print @single_quotation;
 12 print " ----------------------------------ch_5_Q1_-------------------------- ";
 13 =cut
 14
 15 print " ----------------------------------ch_5_Q2_-------------------------- ";
 16 print "What column width would you like?, please input:";
 17 chomp(my $width = <STDIN>);
 18 print "Enter some lines, then press Ctrl-D: "; # or Ctrl-z
 19 my @underscore;
 20 chomp(@underscore = <STDIN>);
 21 #@underscore = <STDIN>;
 22 #print " "."1234567890"x7,"12345 ";
 23 print " "."1234567890"x (($width + 9)/10),"12345 ";
 24                          
 25 =head1                   
 26 foreach(@underscore){    
 27     #print "$_"." ";    
 28     printf "%20s ", $_;
 29 }                        
 30 =cut                     
 31                          
 32 my $semicolons = "%${width}s " x @underscore;
 33 printf "$semicolons", @underscore;
 34 print " ----------------------------------ch_5_Q2_-------------------------- ";