control structures. the if conditional condition must go within parentheses statements come after...

Control Structures

The if Conditional

Condition must go within parentheses Statements come after the curly brace

Example:

if (empty ($name)) {

print ‘please enter a name.’

}

Code Example for the if Conditional 6.2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />

<title>Registration</title> </head> <body> <?php // Script 6.2 - handle_reg.php // Address error handing. ini_set ('display_errors', 1); error_reporting (E_ALL & ~E_NOTICE); // In case register_globals is disabled. $first_name = $_POST['first_name']; $last_name = $_POST['last_name']; $email = $_POST['email']; $password = $_POST['password']; $confirm = $_POST['confirm']; $month = $_POST['month']; $day = $_POST['day']; $year = $_POST['year']; $color = $_POST['color']; print 'Registration Results:'; // Validate the first name. if (empty ($first_name)) {

print 'Please enter your first name.'; } // Validate the last name. if (empty ($last_name)) {

print 'Please enter your last name.'; } // Validate the email address. if (empty ($email)) {

print 'Please enter your email address.'; } // Validate the password. if (empty ($password)) {

print 'Please enter your password.'; } ?> </body> </html>

Using else 6.3 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head>

<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />

<title>Registration</title> </head> <body> <?php // Script 6.3 - handle_reg.php - second version after Script 6.2 // Address error handing. ini_set ('display_errors', 1); error_reporting (E_ALL & ~E_NOTICE); // In case register_globals is disabled. $first_name = $_POST['first_name']; $last_name = $_POST['last_name']; $email = $_POST['email']; $password = $_POST['password']; $confirm = $_POST['confirm']; $month = $_POST['month']; $day = $_POST['day']; $year = $_POST['year']; $color = $_POST['color']; print 'Registration Results:'; // Validate the first name. if (empty ($first_name)) { print 'Please enter your first name.'; }

// Validate the last name. if (empty ($last_name)) { print 'Please enter your last name.'; } // Validate the email address. if (empty ($email)) { print 'Please enter your email address.'; } // Validate the password. if (empty ($password)) { print 'Please enter your password.'; } // Validate the month. if (is_numeric ($month)) { $birthdate = $month . '-'; } else { print 'Please select the month you were born.'; } // Validate the day. if (is_numeric ($day)) { $birthdate .= $day . '-'; } else { print 'Please select the day you were born.'; } // Validate the year. if (is_numeric ($year)) { $birthdate .= $year; } else { print 'Please enter the year you were born as four digits.'; } print "You entered your birthday as $birthdate"; ?> </body> </html>

PHP Operators

Operator Usage Type== Equality Comparison

!= Inequality Comparison

AND/&& And logical

OR/l l Or logical

. Concatenation string

.= Concatenates to the values of a

variable

Concatenation and assignment

Example on operators 6.4 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /> <title>Registration</title> </head> <body> <?php // Script 6.4 - handle_reg.php - third version after Scripts 6.2 and 6.3 // Address error handing. ini_set ('display_errors', 1); error_reporting (E_ALL & ~E_NOTICE); // In case register_globals is disabled. $first_name = $_POST['first_name']; $last_name = $_POST['last_name']; $email = $_POST['email']; $password = $_POST['password']; $confirm = $_POST['confirm']; $month = $_POST['month']; $day = $_POST['day']; $year = $_POST['year']; $color = $_POST['color']; print 'Registration Results:'; // Validate the first name. if (empty ($first_name)) { print 'Please enter your first name.'; }

// Validate the last name. if (empty ($last_name)) { print 'Please enter your last name.'; } // Validate the email address. if (empty ($email)) { print 'Please enter your email address.'; } // Validate the password. if (empty ($password)) { print 'Please enter your password.'; } // Check the two passwords for equality. if ( $password != $confirm ) { print 'Your confirmed password does not match the original password.'; } // Validate the month. if (is_numeric ($month)) { $birthdate = $month . '-'; } else { print 'Please select the month you were born.'; } // Validate the day. if (is_numeric ($day)) { $birthdate .= $day . '-'; } else { print 'Please select the day you were born.'; } // Validate the year. if (is_numeric ($year)) { $birthdate .= $year; } else { print 'Please enter the year you were born as four digits.'; } // Check that they were born before 2004. if ($year >= 2004) { print 'Either you entered your birth year wrong or you come from the future!'; } print "You entered your birthday as $birthdate"; ?> </body> </html>

Using elseif 6.6 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /> <title>Registration</title> </head> <body> <?php // Script 6.6 - handle_reg.php - fifth version after Scripts 6.2, 6.3, 6.4 and 6.5 // Address error handing. ini_set ('display_errors', 1); error_reporting (E_ALL & ~E_NOTICE); // In case register_globals is disabled. $first_name = $_POST['first_name']; $last_name = $_POST['last_name']; $email = $_POST['email']; $password = $_POST['password']; $confirm = $_POST['confirm']; $month = $_POST['month']; $day = $_POST['day']; $year = $_POST['year']; $color = $_POST['color']; print 'Registration Results:'; // Validate the first name. if (empty ($first_name)) { print 'Please enter your first name.'; } // Validate the last name. if (empty ($last_name)) { print 'Please enter your last name.'; } // Validate the email address. if (empty ($email)) { print 'Please enter your email address.'; }

// Validate the password. if (empty ($password)) { print 'Please enter your password.'; } // Check the two passwords for equality. if ($password != $confirm) { print 'Your confirmed password does not match the original password.'; } // Validate the month. if (is_numeric ($month)) { $birthdate = $month . '-'; } else { print 'Please select the month you were born.'; } // Validate the day. if (is_numeric ($day)) { $birthdate .= $day . '-'; } else { print 'Please select the day you were born.'; } // Validate the year. if ( is_numeric ($year) AND strlen ($year) == 4 ) { // Check that they were born before 2004. if ($year >= 2004) { print 'Either you entered your birth year wrong or you come from the future!'; } else { $birthdate .= $year; } // End of 2nd conditional.

} else { // Else for 1st conditional. print 'Please enter the year you were born as four digits.';

} // End of 1st conditional. // Validate the color. if (!$color) { print 'Please select your favorite color.'; }

print "You entered your birthday as $birthdate"; // Get the horoscope sign. if ($month == 1) { // January if ($day <= 19) { $sign = 'Capricorn'; } else { $sign = 'Aquarius'; } } elseif ($month == 2) { // February if ($day <= 18) { $sign = 'Aquarius'; } else { $sign = 'Pisces'; } } elseif ($month == 3) { if ($day <= 20) { $sign = 'Pisces'; } else { $sign = 'Aries'; } } elseif ($month == 4) { if ($day <= 19) { $sign = 'Aries'; } else { $sign = 'Taurus'; } } elseif ($month == 5) { if ($day <= 20) { $sign = 'Taurus'; } else { $sign = 'Gemini'; } } elseif ($month == 6) { if ($day <= 19) { $sign = 'Gemini';

} else { $sign = 'Cancer'; } } elseif ($month == 7) { if ($day <= 22) { $sign = 'Cancer'; } else { $sign = 'Leo'; } } elseif ($month == 8) { if ($day <= 22) { $sign = 'Leo'; } else { $sign = 'Virgo'; } } elseif ($month == 9) { if ($day <= 22) { $sign = 'Virgo'; } else { $sign = 'Libra'; } } elseif ($month == 10) { if ($day <= 22) { $sign = 'Libra'; } else { $sign = 'Scorpio'; } } elseif ($month == 11) { if ($day <= 21) { $sign = 'Scorpio'; } else { $sign = 'Sagittarius'; } } elseif ($month == 12) { if ($day <= 21) { $sign = 'Sagittarius'; } else { $sign = 'Capricorn'; } } print "You are a(n) $sign."; ?> </body> </html>

The Switch Conditional

The switch conditional takes only one possible condition which is the value of a variable. Example:

switch ($variable) {

case “value”:

statements;

break;

}

Switch Code Example 6.7 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /> <title>Registration</title> </head> <body> <?php // Script 6.7 - handle_reg.php - sixth version after Scripts 6.2, 6.3, 6.4, 6.5 and 6.6 // Address error handing. ini_set ('display_errors', 1); error_reporting (E_ALL & ~E_NOTICE); // In case register_globals is disabled. $first_name = $_POST['first_name']; $last_name = $_POST['last_name']; $email = $_POST['email']; $password = $_POST['password']; $confirm = $_POST['confirm']; $month = $_POST['month']; $day = $_POST['day']; $year = $_POST['year']; $color = $_POST['color']; print 'Registration Results:'; // Validate the first name. if (empty ($first_name)) { print 'Please enter your first name.'; } // Validate the last name. if (empty ($last_name)) { print 'Please enter your last name.'; } // Validate the email address. if (empty ($email)) { print 'Please enter your email address.'; }

// Validate the password. if (empty ($password)) { print 'Please enter your password.'; } // Check the two passwords for equality. if ($password != $confirm) { print 'Your confirmed password does not match the original password.'; } // Validate the month. if (is_numeric ($month)) { $birthdate = $month . '-'; } else { print 'Please select the month you were born.'; } // Validate the day. if (is_numeric ($day)) { $birthdate .= $day . '-'; } else { print 'Please select the day you were born.'; } // Validate the year. if ( is_numeric ($year) AND strlen ($year) == 4 ) { // Check that they were born before 2004. if ($year >= 2004) { print 'Either you entered your birth year wrong or you come from the future!'; } else { $birthdate .= $year; } // End of 2nd conditional.

} else { // Else for 1st conditional. print 'Please enter the year you were born as four digits.';

} // End of 1st conditional. // Validate the color. if (!$color) {

print 'Please select your favorite color.'; } print "You entered your birthday as $birthdate"; // Get the horoscope sign. switch ($month) { case 1: if ($day <= 19) { $sign = 'Capricorn'; } else { $sign = 'Aquarius'; } break; case 2: if ($day <= 18) { $sign = 'Aquarius'; } else { $sign = 'Pisces'; } break; case 3: if ($day <= 20) { $sign = 'Pisces'; } else { $sign = 'Aries'; } break; case 4: if ($day <= 19) { $sign = 'Aries'; } else { $sign = 'Taurus'; } break; case 5: if ($day <= 20) { $sign = 'Taurus'; } else { $sign = 'Gemini'; } break; case 6: if ($day <= 19) { $sign = 'Gemini'; } else { $sign = 'Cancer';

} break; case 7: if ($day <= 22) { $sign = 'Cancer'; } else { $sign = 'Leo'; } break; case 8: if ($day <= 22) { $sign = 'Leo'; } else { $sign = 'Virgo'; } break; case 9: if ($day <= 22) { $sign = 'Virgo'; } else { $sign = 'Libra'; } break; case 10: if ($day <= 22) { $sign = 'Libra'; } else { $sign = 'Scorpio'; } break; case 11: if ($day <= 21) { $sign = 'Scorpio'; } else { $sign = 'Sagittarius'; } break; case 12: if ($day <= 21) { $sign = 'Sagittarius'; } else { $sign = 'Capricorn'; } break; } // End of switch. print "You are a(n) $sign."; ?> </body> </html>

The for Loop

PHP supports three kinds of loops: for: performs specific statements for a determined

number of iterations. while: runs until a condition is false foreach: commonly used with arrays

Code Example 6.8 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /> <title>Register</title> </head> <body>  Please complete this form to register: <form action="handle_reg.php" method="post"> First Name: <input type="text" name="first_name" size="20" /> Last Name: <input type="text" name="last_name" size="20" /> Email Address: <input type="text" name="email" size="20" /> Password: <input type="password" name="password" size="20" /> Confirm Password: <input type="password" name="confirm" size="20" /> Date Of Birth: <select name="month"> <option value="">Month</option> <option value="1">January</option> <option value="2">February</option> <option value="3">March</option> <option value="4">April</option> <option value="5">May</option> <option value="6">June</option> <option value="7">July</option> <option value="8">August</option> <option value="9">September</option> <option value="10">October</option> <option value="11">November</option> <option value="12">December</option> </select> <select name="day"> <option value="">Day</option> <?php

// Print out 31 days. for ($d = 1; $d <= 31; $d++) { print "<option value=\"$d\">$d</option>\n"; } ?> </select> <input type="text" name="year" value="YYYY" size="4" /> Favorite Color: <select name="color"> <option value="">Pick One</option> <option value="red">Red</option> <option value="yellow">Yellow</option> <option value="green">Green</option> <option value="blue">Blue</option> </select> <input type="submit" name="submit" value="Register" /> </form> </body> </html>

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