C.3 Chapter 4

C.3.1 Exercise 1:

$population = array('New York, NY' => 8008278,

                    'Los Angeles, CA' => 3694820,

                    'Chicago, IL' => 2896016,

                    'Houston, TX' => 1953631,

                    'Philadelphia, PA' => 1517550,

                    'Phoenix, AZ' => 1321045,

                    'San Diego, CA' => 1223400,

                    'Dallas, TX' => 1188580,

                    'San Antonio, TX' => 1144646,

                    'Detroit, MI' => 951270);

$total_population = 0;

print "<table><tr><th>City</th><th>Population</th></tr>\n";

foreach ($population as $city => $people) {

    $total_population += $people;

    print "<tr><td>$city</td><td>$people</td></tr>\n";

    

}

print "<tr><td>Total</td><td>$total_population</td></tr>\n";

print "</table>\n";

C.3.2 Exercise 2:

Use asort( ) to sort by population.

$population = array('New York, NY' => 8008278,

                    'Los Angeles, CA' => 3694820,

                    'Chicago, IL' => 2896016,

                    'Houston, TX' => 1953631,

                    'Philadelphia, PA' => 1517550,

                    'Phoenix, AZ' => 1321045,

                    'San Diego, CA' => 1223400,

                    'Dallas, TX' => 1188580,

                    'San Antonio, TX' => 1144646,

                    'Detroit, MI' => 951270);

$total_population = 0;

asort($population);

print "<table><tr><th>City</th><th>Population</th></tr>\n";

foreach ($population as $city => $people) {

    $total_population += $people;

    print "<tr><td>$city</td><td>$people</td></tr>\n";

    

}

print "<tr><td>Total</td><td>$total_population</td></tr>\n";

print "</table>\n";

Use ksort( ) to sort by city name.

$population = array('New York, NY' => 8008278,

                    'Los Angeles, CA' => 3694820,

                    'Chicago, IL' => 2896016,

                    'Houston, TX' => 1953631,

                    'Philadelphia, PA' => 1517550,

                    'Phoenix, AZ' => 1321045,

                    'San Diego, CA' => 1223400,

                    'Dallas, TX' => 1188580,

                    'San Antonio, TX' => 1144646,

                    'Detroit, MI' => 951270);

$total_population = 0;

ksort($population);

print "<table><tr><th>City</th><th>Population</th></tr>\n";

foreach ($population as $city => $people) {

    $total_population += $people;

    print "<tr><td>$city</td><td>$people</td></tr>\n";

    

}

print "<tr><td>Total</td><td>$total_population</td></tr>\n";

print "</table>\n";

C.3.3 Exercise 3:

// Separate the city and state name in the array so we can total by state

$population = array('New York'     => array('state' => 'NY', 'pop' => 8008278),

                    'Los Angeles'  => array('state' => 'CA', 'pop' => 3694820),

                    'Chicago'      => array('state' => 'IL', 'pop' => 2896016),

                    'Houston'      => array('state' => 'TX', 'pop' => 1953631),

                    'Philadelphia' => array('state' => 'PA', 'pop' => 1517550),

                    'Phoenix'      => array('state' => 'AZ', 'pop' => 1321045),

                    'San Diego'    => array('state' => 'CA', 'pop' => 1223400),

                    'Dallas'       => array('state' => 'TX', 'pop' => 1188580),

                    'San Antonio'  => array('state' => 'TX', 'pop' => 1144646),

                    'Detroit'      => array('state' => 'MI', 'pop' => 951270));

// Use the $state_totals array to keep track of per-state totals

$state_totals = array( );

$total_population = 0;

print "<table><tr><th>City</th><th>Population</th></tr>\n";

foreach ($population as $city => $info) {

    // $info is an array with two elements: pop (city population)

    // and state (state name)

    $total_population += $info['pop'];

    // increment the $info['state'] element in $state_totals by $info['pop']

    // to keep track of the total population of state $info['state']

    $state_totals[$info['state']] += $info['pop'];

    print "<tr><td>$city, {$info['state']}</td><td>{$info['pop']}</td></tr>\n";

    

}

// Iterate through the $state_totals array to print the per-state totals

foreach ($state_totals as $state => $pop) {

    print "<tr><td>$state</td><td>$pop</td>\n";

}

print "<tr><td>Total</td><td>$total_population</td></tr>\n";

print "</table>\n";

C.3.4 Exercise 4:

An associative array whose keys are students' names and whose values are associative arrays of grade and ID number.

$students = array('James D. McCawley' => array('grade' => 'A+',

                                               'id' => 271231),

                  'Buwei Yang Chao' => array('grade' => 'A', 

                                             'id' => 818211));

An associative array whose key is the item name and whose value is the number in stock.

$stock = array('Woks' => 5, 'Steamers' => 3, 'Heavy Cleavers' => 2, 

               'Light Cleavers' => 6);

An associative array whose key is the day and whose value is an associative array describing the meal. This associative array has a key/value pair for cost and a key/value pair for each part of the meal (entree, side dish, drink).

$lunches = array('Monday' => array('cost' => 1.50,

                                   'entree' => 'Beef Shiu-Mai',

                                   'side' => 'Salty Fried Cake',

                                   'drink' => 'Black Tea'),

                 'Tuesday' => array('cost' => 1.50,

                                    'entree' => 'Clear-steamed Fish',

                                    'side' => 'Turnip Cake',

                                    'drink' => 'Black Tea'),

                 'Wednesday' => array('cost' => 2.00,

                                      'entree' => 'Braised Sea Cucumber',

                                      'side' => 'Turnip Cake',

                                      'drink' => 'Green Tea'),

                 'Thursday' => array('cost' => 1.35,

                                     'entree' => 'Stir-fried Two Winters',

                                     'side' => 'Egg Puff',

                                     'drink' => 'Black Tea'),

                 'Friday' => array('cost' => 2.15,

                                   'entree' => 'Stewed Pork with Taro',

                                   'side' => 'Duck Feet',

                                   'drink' => 'Jasmine Tea'));

A numeric array whose values are the names of family members.
```
$family = array('Bart','Lisa','Homer','Marge','Maggie');
```

An associative array whose keys are the names of family members and whose values are associative arrays of age and relationship.

$family = array('Bart' => array('relation' => 'brother',

                                'age' => 10),

                'Lisa' => array('relation' => 'sister',

                                'age' => 7),

                'Homer' => array('relation' => 'father',

                                 'age' => 36),

                'Marge' => array('relation' => 'mother',

                                 'age' => 34),

                'Maggie' => array('relation' => 'self',

                                  'age' => 1));

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