Learning PHP

Appendix B. Answers to Exercises

Chapter 2

Exercise 1

1. The opening PHP tag should be just <?php with no space between the <? and php.
2. Because the string I'm fine contains a ', it should be surrounded by double quotes ("I'm fine") or the ' should be escaped ('I\'m fine').
3. The closing PHP tag should be ?>, not ??>. Or, if this code were the last thing in its file, the closing PHP tag could be omitted.

Exercise 2

$hamburger = 4.95;
$shake = 1.95;
$cola = 0.85;

$tip_rate = 0.16;
$tax_rate = 0.075;

$food = (2 * $hamburger) + $shake + $cola;
$tip = $food * $tip_rate;
$tax = $food * $tax_rate;

$total = $food + $tip + $tax;

print 'The total cost of the meal is $' . $total;

Exercise 3

$hamburger = 4.95;
$shake = 1.95;
$cola = 0.85;

$tip_rate = 0.16;
$tax_rate = 0.075;

$food = (2 * $hamburger) + $shake + $cola;
$tip = $food * $tip_rate;
$tax = $food * $tax_rate;

$total = $food + $tip + $tax;

printf("%d %-9s at \$%.2f each: \$%5.2f\n", 2, 'Hamburger', $hamburger,
       2 * $hamburger);
printf("%d %-9s at \$%.2f each: \$%5.2f\n", 1, 'Shake', $shake, $hamburger);
printf("%d %-9s at \$%.2f each: \$%5.2f\n", 1, 'Cola', $cola, $cola);
printf("%25s: \$%5.2f\n", 'Food Total', $food);
printf("%25s: \$%5.2f\n", 'Food and Tax Total', $food + $tax);
printf("%25s: \$%5.2f\n", 'Food, Tax, and Tip Total', $total);

Exercise 4

$first_name = 'Srinivasa';
$last_name = 'Ramanujan';
$name = "$first_name $last_name";
print $name;
print strlen($name);

Exercise 5

$n = 1; $p = 2;
print "$n, $p\n";

$n ...