Bad Wolf's PHP Learning Tutorial Day 2_PHP Tutorial

1. Basic writing:

echo "Buy a virtual host and find a bad wolf! www.winshell.cnn";
//Here is the content to be written in php! "n" means line break ";" means end If there are too many lines, add them to prevent errors.

2. Program execution:
The program runs from top to bottom, from right to left.
You can only turn back when encountering special controls.
The way the program stops is the end of the run, the end of the error, the end of the command.
3. When writing the program, pay attention to
Try not to use unused variables, such as a=123, but the program does not use it, that is If it is wasted, the program will slow down. Reduce test writing and reduce waste code. For example, to determine whether the other party is a male or female alien.
Consider the flexibility of the program (don’t use anything you don’t need to write, it is convenient for debugging, Press the tab key to change the line. Use the same words for similar words. Develop good programming habits. There must be rules)
Indentation and brackets must be symmetrical. Control of the amount of data (length of variable names, shorter rules are better) Variables such as :aaa.php?id=2222
4. Quoting file method:
require("file name"); If the import fails, an Error will be reported! Easy to remember word "Ruiqard"
include ("File name"); If the import fails, it will not issue a warning (Warning)! The easy-to-remember word "Yin Ke Ru De"
There are other require("db.txt"); include("db. txt"); refers to the db.txt file in the same directory.
If db.txt does not exist, a page error will occur when writing require.
If db.txt does not exist, the include writing method will only report an error on the current line.
5. Program comments
//Single-line comments, double-digit comments /* */ Xing Xing - Xing Xing
/* Write the content to be commented here. You can write it in any way, or as much as you want! You can’t see me */
6. Constants and variables
Constant ex. For example, pi is a common number, haha!
Variable ex. $x, $y, $z..
7. The form of constants
true true
fals false
8. The form of variables
string string
integer integer 123456780
double floating point number 1.2 with decimal point
array array
object object
9. Use of variables (" variable quotes \backslash n line feed r send t jump TAB)
Use reserved words
plus $ to use
form conversion Loose
Declaration-free
About global variables global $variables
10. Quotes for variables
Single quotes '' have no effect.
Double quotes ""php will handle it for you.
11. $a = "Bad Wolf";
$b = "Sell virtual host!";
echo "$a! $a! It's $b!!!";
12. Operation symbols
Numbers, words, logic...
An important part of the program
Understanding and looking up tables...
13. Arithmetic operations
+addition - subtraction *multiplication/division % take the remainder (8/3 remainder Yes 2) ++ Accumulate 1 - Decrement 1
14. String operation
. Point = equal to
15. Set operation
= Connect the value on the right to the left
+= Add the value on the right to the left
-= Subtract the value on the right to the left
*= Multiply the value on the left to the right
/= Divide the value on the left to the right
%= Divide the value on the left Take the remainder of the value on the right
.= Add the string on the right to the left
I tested the code I wrote today! I also need to create a db.txt in the same directory and write some boring stuff

Copy code The code is as follows:

require("db.txt");
//How to quote the file, you require("File content!"); If the file content cannot be found, everything will stop!
echo"
";
//A newline is displayed here< br>
include("db.txt");
//The way to reference the file is include("file content!"); If the file content cannot be found, an error message will only appear on the current line!
echo "
";
//A newline is displayed here

echo "Buy a virtual host and find a bad wolf!
www.winshell.cnn";
//Here It's php to write the content! "n" means line break ";" End, if there are many lines, add
/* You can't see me! You can't see me! You can't see me! You can't see me ! */
?>


$a = "Bad Wolf";
$b = "Selling virtual hosts!";
echo"$a! $a! Is $b!!!";
echo"
";
echo'$a! $a! Is $b!!!//Here is a single The quotation mark part will not be processed.'; //No processing will be done within the single quotation mark!
?>
 
;
$b = "Okay!";
$c = $a . $b ; //Add the contents of $a and $b to $c
echo $c. " < p>";
$c = $c . $a .$b;
echo $c. "

";
?>
$ a = "8";
$b = "2";
$c = "3";
echo $a+$b. "
n"; // This n View source file You will see line breaks!
echo $a-$b. "
n";
echo $a*$b. "
n";
echo $a /$b. "
n";
echo $a%$b. "
n";
$a++;
echo $a."
n" ;
$c--;
echo $c."
n";
?>

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www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/319114.htmlTechArticle1. Basic writing method: echo "Buy a virtual host and find a bad wolf! www.winshell.cnn"; //Here It is php to write the content! "n" means line break ";" means the ending line must be added if there are too many. Otherwise, an error will be reported. 2. Execution of the program: Process...