【学习笔记】PHP-函数 数组 为什么么有class?

<?php

header("Content-Type:text/html;charset=utf-8");
//function and class
echo ‘<h1>Stydy function and class</h1>‘;
$h = date(‘H‘);//get time
//if(){...}elseif(){...}else{...}	
if($h<12){
    echo "is $h".":00 now at am<br>"; 
}else{//elseif($h>=12)
		echo "is $h".":00 now at pm<br>";
}

$sw = "10";

switch($sw){
    case 10://居然是执行==不是===
    echo "‘10‘ == 10<br>";

    case "10":
    echo "‘10‘ != 10<br>";
    
    case 100:
    echo "what will happen without break?<br>";
    break;
    
    default:
    echo "i‘m success<br>";
}
//while(){}... and do{...}while()
//来来来for大冒泡走一个

$ints = array(54,36,23,74,66,87,58,22,29);

$i = count($ints);
for($j = $i;$j>0;$j--){//for作为语句，里面创建的变量是全局的
	echo ‘j = ‘.$j.‘;i = ‘.$i.‘<br>‘;
}

echo $j.‘<br>‘;//0

for(;$i>1;$i--){
    for($j = 0;$j<$i;$j++){
        if($ints[$j]<$ints[$j+1])
            swap($ints[$j],$ints[$j+1]);//函数可以先使用，再创建，这里相当于声明，类似于变量
    }
}

function swap(&$x,&$y){//形参？&引用
    static $r = 0;
    echo ‘run swap ‘.$r.‘ times;‘;
	$t = $x;
    $x = $y;
    $y = $t;
    $r++;
}

echo ‘<h2>DO:</h2>‘;
foreach($ints as $int){//$int为全局变量 for in
	echo $int.‘;‘;
}
echo ‘<br>‘;
sort($ints);
echo ‘<h2>UO:</h2>‘;
foreach($ints as $int){//$int为全局变量 for in
    echo $int.‘;‘;
}
echo ‘<br>‘;
var_dump($ints[0]);//int 排序不会改变类型
echo ‘<br>‘;

define("gbChan",5);
$glb = 20;
function askGlb(){
    echo gbChan.$glb.‘<br>‘;//5 常量全局
    echo gbChan.$GLOBALS[‘glb‘].‘<br>‘;//520 超全局
    
}

askGlb();

?>