Workshop

Quiz

1:What were the bugs in the Listing 12.1?
2:If no files are given on the command line, reading <> returns
  1. undef

  2. lines from standard input

  3. True

3:The Perl debugger can print Perl statements as they execute. This is called trace mode. How do you put the debugger into trace mode? (Hint: You need to look at the debugger's help message for this answer.)
  1. Use the T command, for trace

  2. Use The t command, for trace

Answers

A1: First, in line 15 the range (20..0) is not valid. The range operator—..—does not count down, only up. This line should be changed to a for($_=20; $_>-1; $_—) loop, reverse(0..20) or something similar. Second, at line 10 the $mess=s/glasses/glass/ looks like a substitution on $mess, but it's not. The substitution is actually ...

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