Learning PHP, MySQL, and JavaScript

Chapter 4 Answers

Question 4-1

In PHP TRUE represents the value 1 and FALSE represents NULL, which can be thought of as “nothing” and is output as the empty string.

Question 4-2

The simplest forms of expressions are literals (such as numbers and strings) and variables, which simply evaluate to themselves.

Question 4-3

The difference between unary, binary and ternary operators is the number of operands each requires (one, two, and three, respectively).

Question 4-4

The best way to force your own operator precedence is to place parentheses around subexpressions to which you wish to give high precedence.

Question 4-5

Operator associativity refers to the direction of processing (left-to-right or right-to-left).

Question 4-6

You use the identity operator when you wish to bypass PHP’s automatic operand type changing (also called type casting).

Question 4-7

The three conditional statement types are if, switch, and the ? operator.

Question 4-8

To skip the current iteration of a loop and move on to the next one, use a continue statement.

Question 4-9

Loops using for statements are more powerful than while loops, because they support two additional parameters to control the loop handling.

Question 4-10

Most conditional expressions in if and while statements are literal (or Boolean) and therefore trigger execution when they evaluate to TRUE. Numeric expressions trigger execution when they evaluate to a nonzero value. String expressions trigger execution when they evaluate to a nonempty string. A NULL value is ...