Merge branch 'coding-horror:main' into main

22_Change/perl/change.pl

@@ -0,0 +1,68 @@
+#!/usr/bin/perl
+
+use v5.24; # for say and use strict
+use warnings;
+
+sub get_pennies {
+  my $query = shift;
+
+  print "$query? ";
+  my $in = <>;
+  chomp $in;
+  $in =~ /([\d.]+)/; # the first match of digits and decimal points
+  return int( $1 * 100 );
+}
+
+sub make_change {
+  my $change = shift;
+
+  state %change_options = (
+    'Penny' => { value => 1, plural => 'Pennies' },
+    'Nickel' => { value => 5 },
+    'Dime' => { value => 10 },
+    'Quarter' => { value => 25 },
+    'One Half Dollar' => { value => 50 },
+    'One Dollar Bill' => { value => 100 * 1 },
+    'Five Dollar Bill' => { value => 100 * 5 },
+    '10 Dollar Bill' => { value => 100 * 10 },
+  );
+
+  foreach my $unit ( sort { $change_options{$b}->{value} <=> $change_options{$a}->{value} } keys %change_options ) {
+    my $value = $change_options{$unit}->{value};
+    next if $value > $change;
+    my $number = int( $change / $value );
+    if ( $number > 1 ) {
+      $unit = exists $change_options{$unit}->{plural} ? $change_options{$unit}->{plural} : "${unit}s";
+    }
+    say "$number $unit";
+    $change -= $number * $value;
+  }
+}
+
+print <<'__END_OF_INTRO';
+                              Change
+               Creative Computing  Morristown, New Jersey
+
+
+I, Your friendly microcomputer, will determine
+the correct change for items costing up to $100.
+
+
+__END_OF_INTRO
+
+while ( 1 ) {
+  my $cost = get_pennies( 'Cost of item' );
+  my $payment = get_pennies( 'Amount of payment');
+
+  my $change = $payment - $cost;
+  my $change_formatted = sprintf( "%.2f", $change / 100 );
+  if ( $change == 0 ) {
+    say 'Correct amount, thank you.';
+  } elsif ( $change < 0 ) {
+    say 'Sorry, you have short-changed me $', abs($change_formatted);
+  } else {
+    say 'Your change, $', $change_formatted;
+    make_change( $change );
+    say "Thank you, come again\n\n";
+  }
+}