C.8 Chapter 9
C.8.1 Exercise 1:
$stamp = mktime(19,45,0,10,20,2004);
print strftime('Today is day %d of %B and day %j of the year %Y. The time is %I:%M %p
(also known as %H:%M).', $stamp);
C.8.2 Exercise 2:
$stamp = mktime(19,45,0,10,20,2004);
print 'Today is day '.date('d',$stamp).' of '.date('F',$stamp).' and day '.
(date('z',$stamp)+1);
print ' of the year '.date('Y',$stamp).'. The time is '.date('h:i A',$stamp);
print ' (also known as '.date('H:i',$stamp).').';
C.8.3 Exercise 3:
<?php
print '<table>';
print '<tr><th>Year</th><th>Labor Day</th></tr>';
for ($year = 2004; $year <= 2020; $year++) {
// Get the timestamp for September 1 of $year
$stamp = mktime(12,0,0,9,1,$year);
// Advance to the first monday
$stamp = strtotime('monday', $stamp);
print "<tr><td>$year</td><td>";
print date('F j', $stamp);
print "</td></tr>\n";
}
print '</table>';
?>
C.8.4 Exercise 4:
<?php
require 'formhelpers.php';
// Set up arrays of months, days, years, hours, and minutes
$months = array(1 => 'January', 2 => 'February', 3 => 'March', 4 => 'April',
5 => 'May', 6 => 'June', 7 => 'July', 8 => 'August',
9 => 'September', 10 => 'October', 11 => 'November',
12 => 'December');
$days = array( );
for ($i = 1; $i <= 31; $i++) { $days[$i] = $i; }
$years = array( );
for ($year = date('Y') -1, $max_year = date('Y') + 5; $year < $max_year; $year++) {
$years[$year] = $year;
}
if ($_POST['_submit_check']) {
// If validate_form( ) returns errors, pass them to show_form( )
if ($form_errors = validate_form( )) {
show_form($form_errors);
} else {
// The submitted data is valid, so process it
process_form( );
}
} else {
// The form wasn't submitted, so display
show_form( );
}
function show_form($errors = '') {
global $months, $days, $years;
// If the form is submitted, get defaults from submitted variables
if ($_POST['_submit_check']) {
$defaults = $_POST;
} else {
// Otherwise, set our own defaults: one month from now
$default_timestamp = strtotime('+1 month');
$defaults = array('month' => date('n', $default_timestamp),
'day' => date('j', $default_timestamp),
'year' => date('Y', $default_timestamp));
}
// If errors were passed in, put them in $error_text (with HTML markup)
if ($errors) {
print 'You need to correct the following errors: <ul><li>';
print implode('</li><li>',$errors);
print '</li></ul>';
}
print '<form method="POST" action="'.$_SERVER['PHP_SELF'].'">';
print 'Enter a date and time:';
input_select('month',$defaults,$months);
print ' ';
input_select('day',$defaults,$days);
print ' ';
input_select('year',$defaults,$years);
print '<br/>';
input_submit('submit','Find Tuesdays');
print '<input type="hidden" name="_submit_check" value="1"/>';
print '</form>';
}
function validate_form( ) {
global $months, $days, $years;
$errors = array( );
if (! array_key_exists($_POST['month'], $months)) {
$errors[ ] = 'Select a valid month.';
}
if (! array_key_exists($_POST['day'], $days)) {
$errors[ ] = 'Select a valid day.';
}
if (! array_key_exists($_POST['year'], $years)) {
$errors[ ] = 'Select a valid year.';
}
// Make sure the submitted date is in the future
// Find epoch timestamp for midnight today
// Leaving off month, day, and year arguments make them
// default to today
$midnight = mktime(0,0,0);
// Find epoch timestmap for midnight on the submitted date
$midnight_submitted = mktime(0,0,0,$_POST['month'], $_POST['day'],
$_POST['year']);
if ($midnight_submitted <= $midnight) {
$errors[ ] = 'Enter a date in the future.';
}
return $errors;
}
function process_form( ) {
// Make an epoch timestamp for the user-entered date
$midnight_submitted = mktime(0,0,0,$_POST['month'], $_POST['day'],
$_POST['year']);
// Get the epoch timestamp for the next Tuesday (including today,
// if today is Tuesday.
$timestamp = strtotime('tuesday');
if ($timestamp >= $midnight_submitted) {
print 'There are no Tuesdays between ';
print date('l, F j, Y');
print ' and ';
print date('l, F j, Y.', $midnight_submitted);
} else {
while ($timestamp < $midnight_submitted) {
// Print a formatted date string for $timestamp (which is a Tuesday)
print date('l, F j, Y', $timestamp);
print '<br/>';
// Add a week to $timestamp
$timestamp = strtotime('+1 week', $timestamp);
}
}
}
?>
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