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|
#!perl
################################################################################
=comment
Perl Weekly Challenge 282
=========================
TASK #2
-------
*Changing Keys*
Submitted by: Mohammad Sajid Anwar
You are given an alphabetic string, $str, as typed by user.
Write a script to find the number of times user had to change the key to type
the given string. Changing key is defined as using a key different from the last
used key. The shift and caps lock keys won't be counted.
Example 1
Input: $str = 'pPeERrLl'
Output: 3
p -> P : 0 key change
P -> e : 1 key change
e -> E : 0 key change
E -> R : 1 key change
R -> r : 0 key change
r -> L : 1 key change
L -> l : 0 key change
Example 2
Input: $str = 'rRr'
Output: 0
Example 3
Input: $str = 'GoO'
Output: 1
=cut
################################################################################
#--------------------------------------#
# Copyright © 2024 PerlMonk Athanasius #
#--------------------------------------#
#===============================================================================
=comment
Interface
---------
1. If no command-line arguments are given, the test suite is run. Otherwise:
2. A single, alphabetic, string is entered on the command-line.
=cut
#===============================================================================
use v5.32; # Enables strictures and warnings
use Const::Fast;
use Test::More;
const my $USAGE => <<END;
Usage:
perl $0 <str>
perl $0
<str> An alphabetic string
END
#-------------------------------------------------------------------------------
BEGIN
#-------------------------------------------------------------------------------
{
$| = 1;
print "\nChallenge 282, Task #2: Changing Keys (Perl)\n\n";
}
#===============================================================================
MAIN:
#===============================================================================
{
my $argc = scalar @ARGV;
if ($argc == 0)
{
run_tests();
}
elsif ($argc == 1)
{
my $str = $ARGV[ 0 ];
$str =~ / ^ [A-Za-z]* $ /x or error( 'Invalid input string' );
print qq[Input: \$str = "$str"\n];
my $key_changes = count_key_changes( $str );
print "Output: $key_changes\n";
}
else
{
error( "Expected 1 or 0 command-line arguments, found $argc" );
}
}
#-------------------------------------------------------------------------------
sub count_key_changes
#-------------------------------------------------------------------------------
{
my ($str) = @_;
my $changes = 0;
my @chars = split //, $str;
for my $i (1 .. $#chars)
{
++$changes unless lc $chars[ $i - 1 ] eq lc $chars[ $i ];
}
return $changes;
}
#-------------------------------------------------------------------------------
sub run_tests
#-------------------------------------------------------------------------------
{
print "Running the test suite\n";
while (my $line = <DATA>)
{
chomp $line;
my ($test_name, $str, $expected) = split / \| /x, $line;
for ($test_name, $str, $expected)
{
s/ ^ \s+ //x;
s/ \s+ $ //x;
}
my $key_changes = count_key_changes( $str );
is $key_changes, $expected, $test_name;
}
done_testing;
}
#-------------------------------------------------------------------------------
sub error
#-------------------------------------------------------------------------------
{
my ($message) = @_;
die "ERROR: $message\n$USAGE";
}
################################################################################
__DATA__
Example 1|pPeERrLl|3
Example 2|rRr |0
Example 3|GoO |1
Empty | |0
|
