The Art of Debugging with GDB, DDD, and Eclipse

Perl

We will use the following example, textcount.pl, which computes statistics on text files:

 1   #! /usr/bin/perl
 2
 3   # reads the text file given on the command line, and counts words,
 4   # lines, and paragraphs
 5
 6   open(INFILE,@ARGV[0]);
 7
 8   $line_count = 0;
 9   $word_count = 0;
10   $par_count = 0;
11
12   $now_in_par = 0; # not inside a paragraph right now
13
14   while ($line = <INFILE>) {
15      $line_count++;
16      if ($line ne "\n") {
17         if ($now_in_par == 0) {
18            $par_count++;
19            $now_in_par = 1;
20         }
21         @words_on_this_line = split(" ",$line);
22         $word_count += scalar(@words_on_this_line);
23      }
24      else {
25         $now_in_par = 0;
26      }
27   }
28
29   print "$word_count $line_count $par_count\n";

The program counts the number of words, lines, and paragraphs ...