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#+SETUPFILE: ~/.emacs.d/org-templates/level-2.org
#+HTML_LINK_UP: ../index.html
#+OPTIONS: toc:2
#+EXPORT_FILE_NAME: index
#+DATE: 2021-02-02
#+TITLE: Challenge 098
* Task 1 - Read N-characters
You are given file =$FILE=.
Create subroutine =readN($FILE, $number)= returns the first n-characters
and moves the pointer to the =(n+1)th= character.
** Raku
- Program: [[file:raku/ch-1.raku]]
=readN= is defined as such:
#+BEGIN_SRC raku
sub readN (
IO $file, Int $chars --> Str
) {
...
}
#+END_SRC
The pointer index is stored in a state array (=%pointers=). It's stores
the pointer separately for each file. It's initialized with 0.
#+BEGIN_SRC raku
# %pointers stores the pointer index.
state Int %pointers;
%pointers{$file} = 0 without %pointers{$file};
#+END_SRC
The pointer is updated & required string is returned.
#+BEGIN_SRC raku
with %pointers{$file} -> $idx {
%pointers{$file} += $chars;
return $file.slurp.substr($idx, $chars);
}
#+END_SRC
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