Chapter 1 - PHP Crash Course

Question 0

date(‘h’);

Answer 0

12-hour format with leading zeros

Example: 01 through 12

Question 1

date(‘H’);

Answer 1

24-hour format with leading zeros

Example: 00-23

Question 2

date(‘i’);

Answer 2

Minutes with leading zeros

Example: 00 to 59

Question 3

date(‘j’);

Answer 3

Day of the month without leading zeros

Question 4

date(‘F’);

Answer 4

Full name of the month

Example: January

Question 5

date(‘Y’);

Answer 5

The year using 4 digits

Example: 2015

Question 6

How do you write the date function?

Answer 6

date(‘DATE PROPERTIES GO HERE’);

Example: date(‘F jS Y, h:ia’);
Reads: January 6th 2015, 6:14pm

Question 7

How do you access a form variable?

Answer 7

$_POST[‘FIELD NAME’];

Example: $_POST[‘tireqty’];

Then you can assign that value to a variable for easy use:

Example: $tireqty = $_POST[‘tireqty’];

Question 8

How do you write a form field to the page?

Answer 8

echo $tireqty.’ tires<br></br>’;

Or

echo “$tireqty. tires<br></br>”;

Question 9

How do you use the heredoc syntax for write large strings?

Answer 9

echo <<<theEnd
   line 1
   line 2
   line 3
theEnd

Question 10

What are PHP’s 6 data types?

Answer 10

Integer: wholes numbers
Float/double: numbers with decimals
String: string of characters
Boolean: true or false
Array: storing multiple data items
Object: storing instances of classes

Question 11

What is type casting?

Answer 11

Taking the value of a variable and interpreting it as another data type and storing that value in another variables.

Example:
$totalqty = 0;
$totalamount = (float)$totalqty;

Question 12

What are variable variables?

Answer 12

Variable variables let you change the name of a variable dynamically. It works by using the value of one variable as the name of another.

Example:
$varname = ‘tireqty’;

$$varname = 5;
Which is now the same as:
$tireqty = 5;

Question 13

What is a constant and how do you define one?

Answer 13

It stores a value like a variable, but it’s value is set once and then cannot be changed elsewhere in the script.

Example:
define(‘TIREPRICE’, 100);

*** Constants are set to uppercase by convention, so that it may be easier to point them out

Question 14

How do you write a combined assignment operator?

Answer 14

$a += 5;

Which is the same as:

$a = $a + 5;

Question 15

What is a pre-increment or pre-decrement?

Answer 15

++$a or –$a

Which has the effect of first incrementing $a by 1 and second, returning the incrementing value.

Question 16

What is a post-increment or post-decrement?

Answer 16

$a++ or $a–

First the value of $a is returned and printed and second, it’s incremented.

Question 18

What is a reference operator?

Answer 18

( & ) is the reference operator. It is placed before the variable name and used to avoid making a copy of that variable.

Question 19

What is the comma ( , ) operator?

Answer 19

It separates function arguments and other lists of items.

Question 20

What is the “ new “ and the “ -> “ operator?

Answer 20

They’re used to instantiate a class and access class members.

Question 21

What is the Ternary Operator?

Answer 21

( ?: ) Question mark colon
Its similar to an if-else statement.

Example:
($grade >= 50 ? ‘Passed’ : ‘Failed’);

Question 22

What is the Error Suppression operator?

Answer 22

( @ ) or at sign
Can be used in front of any expression; Anything that generates or has a value.

Example:
$a = @(57/0);

Without the @ operator, this line generates a divide-by-zero warning.

Question 23

What is the Execution Operator?

Answer 23

( ` ` ) or backticks

Php attempts to execute whatever is contained between the backticks as a command at the server’s command line.

Example:
$out = ls -la;
echo ‘<pre>’.$out.’</pre>’;

Question 24

What is instanceof ?

Answer 24

( instanceof ) is a Type Operator. Allows you to check whether an object is an instance of a particular class.

Example:
class sampleClass();
$myObject = new sampleClass();
if ($myOject instanceof sampleClass)
echo "myObject is an instance of sampleClass";

Question 25

Explain gettype();

Answer 25

After passing it a variable it returns the type name (bool, int, double, string, array, object, resource or NULL).

Example:
$a = 56;
echo gettype($a). '<br />';

Question 26

Expain settype();

Answer 26

First you add the variable then the type you would like it to change to.

Example:
$a = 56;
settype($a, 'double');
echo gettype($a);

Question 27

is_array();

Answer 27

Checks whether the variable is an array.

Question 28

is_double(); is_float(); is_real();

Answer 28

All are the same function. Checks whether the variable is a float.

Question 29

is_long(); is_int(); is_integer();

Answer 29

All are the same function. Checks whether the variable is an integer.

Question 30

is_string();

Answer 30

Checks whether the variable is a string.

Question 31

is_bool();

Answer 31

Checks whether the variable is a boolean.

Question 32

is_object();

Answer 32

Checks whether the variable is an object.

Question 33

is_resource();

Answer 33

Checks whether the variable is a resource.

Question 34

is_null();

Answer 34

Checks whether the variable is null.

Question 35

is_scaler();

Answer 35

Checks whether the variable is scaler, that is, an integer, boolean, string or float.

Question 36

is_numeric();

Answer 36

Checks whether the variable is any kind of number or a numeric string.

Question 37

is_callable();

Answer 37

Check whether the variable is the name of a valid function.

Question 38

isset();

Answer 38

Its used to test a variable. First you pass it a variable name as an argument and it returns true if it exists and false otherwise. You can also pass in comma separated list of variables and it will check them all.

Example:
echo ‘isset($tireqty) : ‘.isset($tireqty) .’<br></br>’;

Question 39

unset();

Answer 39

This function gets rid of the variable it is passed.

Example:
echo ‘unset($tireqty) : ‘.unset($tireqty) .’<br></br>’;

Question 40

empty();

Answer 40

Checks to see if a variable exists and has a nonempty, nonzero value. It returns true or false accordingly.

Example:
echo ‘empty($tireqty) : ‘.empty($tireqty) .’<br></br>’;

Question 41

How do you write a switch statement?

Answer 41

switch($find) {
   case "a" :
      echo "<p>Regular Customer</p>;
      break;
   case "b" :
      echo "<p>Customer referred by TV</p>;
      break;
   case "c" :
      echo "<p>Customer referred by phone</p>;
      break;
   default :
      echo "<p>We do no know how this customer found us</p>";
}

Question 42

How do you write a while loop?

Answer 42

$distance = 50;
while ($distance ;

$distance += 50;
}

Question 43

How do you write a for loop?

Answer 43

for ($distance = 50; $distance ;

}

Question 44

How do you write a do…while loop?

Answer 44

Do…while loops always run at least once.

$num = 100;
do {
echo $num.”<br></br>”;
} while ($num < 1);

This will only run once because 100 will never be less then 1.

Question 45

What does break; do?

Answer 45

Use when you want to stop executing a loop.

Question 46

What does continue; do?

Answer 46

Use when you want to jump to the next loop iteration.

Question 47

What does exit; do?

Answer 47

Use when you are finished with the entire php script.