4) PHP naming rules, value-transfer method

(1) Naming rules:

including variable names, class names, interface name functions, and so on

① Basic Rules:

Use only lowercase letters, underscores, or numbers

Number cannot start

Cannot repeat with environment and system keywords (for example, if,else,function)

② Hump Type: Name Nameschool myfather

Pascal named: MyName nameschool Myfther

Underline interval: My_name my_father

(2) The method of passing values between variables:

① in PHP, the default is value passing

To refer to a pass, you use &

1 $v 1=;                2 $v 2=$v 1;              This occurred a value passed 3 $v 3= $v 1+;        This does not occur value passed

(3) Reference passing:

1$v 1 =411;2$v 2=&$v 1;3$v 1 =Ten;4 echo $v 2;5 6 7The resulting output is:Ten(same as $V1)8 9 Ten But if the value is passed: One      A$v 1 =411; -$v 2 =$v 1; -$v 1 =Ten; the echo $v 2; -    -  -The result is:411(As with the beginning $v1)

4) PHP naming rules, value-transfer method