PHP Lesson 5 Automatic Type Conversion and Process Control

PHP Lesson 5 Automatic Type Conversion and Process Control_PHP Tutorial

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Release： 2016-07-13 10:19:48

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PHP Lesson 5 Automatic Type Conversion and Process Control

Learning Summary:

1. Understand what automatic type conversion is

2. Understand basic flow control statements

3. Example: How to write a calendar table

Automatic type conversion

1) Convert integer to string

echo $num."abc";

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2) Convert string to integer
$str+3;
3) Convert to Boolean type
False case 0 "" "0" false array() null undefined

4) Forced type conversion

(int)$str
(float)$str
(string)$str

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5)Constant

define("HOST","localhost");

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6)Operator
①One yuan
++ --

②Binary
= - * / %
= += -= *= /= %=
> >= < <= == != === !==< <= == != === !==
&& || !

③Three yuan
? :

Process Control:
1. Process control
2. Function

Process control:

1. Branch structure
if...elseif....else
switch...case
If the condition is a fixed value, use the switch statement

2. Loop control
for
while

3. Abort the loop
break: end directly

<?PHP
 	header("content-type:text/html;charset=utf-8");
	
	for($i=1;$i<10;$i++){
		if($i==3){
			break;
		} else{
				echo $i."<br>";
		}
	}
		
	?>//1 2

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continue: End this loop

<?PHP 	header("content-type:text/html;charset=utf-8");
	
	for($i=1;$i<10;$i++){
		if($i==3){
			continue;
		} else{
				echo $i."<br>";
		}
	}
		
	?>//1 2 4 5 6 7 8 9

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Tips: exit means suspending the following program

echo date("w");
date 中w表示星期几
<?PHP
 	header("content-type:text/html;charset=utf-8");
	echo date("Y-M-D");//分别表示年月日
	exit;
	echo "John";
	?>

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5. The remaining part
1.do...while

				<?php
		 
		 	$score=31;
			do{
				echo "<h1>{$score}</h1>";
			}while($score>=60);
		?>

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4. Multiplication table

<?php
		    for($i=1;$i<=9;$i++){
		    	for($j=1;$j<=$i;$j++){
		    		echo "$i*$j=".$i*$j." ";
		    	}
		    	echo "<br>";
		    }
	?>

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3. PHP implements calendar table

Calendar form:
1. Two-layer for loop
2. Change colors every other row
3. Use if conditional judgment
4.Change the header encoding

<?php
  header("content-type:text/html;charset=utf-8");
	$days= 31;
	
	echo "<table width=&#39;700px&#39; border=&#39;1px&#39;>";
	for($i=1;$i<=$days;){
		echo "<tr>";
		for($j=0;$j<7;$j++){
			if($i>$days){
				echo "<td>&#160;</td>";
			} else{
			echo "<td>{$i}</td>";
			}
				$i++;
		}
		echo "</tr>";
		
	}
	
	echo "</table>";
?>

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Add background color

<?php
  header("content-type:text/html;charset=utf-8");
	$days= 31;
	
	echo "<table width=&#39;700px&#39; border=&#39;1px&#39;>";
	for($i=1;$i<=$days;){
		
		$k++;
		
		if($k%2==1){
			echo "<tr bgcolor=&#39;#cccccc&#39;>";
		}else{
			echo "<tr>";
		}
		
		for($j=0;$j<7;$j++){
			if($i>$days){
				echo "<td>&#160;</td>";
			} else{
			echo "<td>{$i}</td>";
			}
				$i++;
		}
		echo "</tr>";
		
	}
	
	echo "</table>";
?>
	中止脚本
	
		2.exit();中止脚本使用
	    3.die();
			    <?php
		 
		 echo "11111<br>";
		 die("从这儿开始脚本中止");
		 echo "2222222";
		?>

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