Add all the A tasks

Task/Align-columns/PHP/align-columns.php

@@ -0,0 +1,47 @@
+<?php
+$j2justtype = array('L' => STR_PAD_RIGHT,
+                    'R' => STR_PAD_LEFT,
+                    'C' => STR_PAD_BOTH);
+
+/**
+ Justify columns of textual tabular input where the record separator is the newline
+ and the field separator is a 'dollar' character.
+ justification can be L, R, or C; (Left, Right, or Centered).
+
+ Return the justified output as a string
+*/
+function aligner($str, $justification = 'L') {
+  global $j2justtype;
+  assert(array_key_exists($justification, $j2justtype));
+  $justtype = $j2justtype[$justification];
+
+  $fieldsbyrow = array();
+  foreach (explode("\n", $str) as $line)
+    $fieldsbyrow[] = explode('$', $line);
+  $maxfields = max(array_map('count', $fieldsbyrow));
+
+  foreach (range(0, $maxfields-1) as $col) {
+    $maxwidth = 0;
+    foreach ($fieldsbyrow as $fields)
+      $maxwidth = max($maxwidth, strlen($fields[$col]));
+    foreach ($fieldsbyrow as &$fields)
+      $fields[$col] = str_pad($fields[$col], $maxwidth, ' ', $justtype);
+    unset($fields); // see http://bugs.php.net/29992
+  }
+  $result = '';
+  foreach ($fieldsbyrow as $fields)
+    $result .= implode(' ', $fields) . "\n";
+  return $result;
+}
+
+$textinfile = 'Given$a$text$file$of$many$lines,$where$fields$within$a$line$
+are$delineated$by$a$single$\'dollar\'$character,$write$a$program
+that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$
+column$are$separated$by$at$least$one$space.
+Further,$allow$for$each$word$in$a$column$to$be$either$left$
+justified,$right$justified,$or$center$justified$within$its$column.';
+
+foreach (array('L', 'R', 'C') as $j)
+  echo aligner($textinfile, $j);
+
+?>