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PHP basic operators and control structure process code examples
PHP basic operators and control structure process code examples
PHP introductory tutorial operator and control structure process, combined with examples, a detailed analysis of PHP's basic assignment, auto-increment, comparison, ternary operator, as well as if statements, switch statements, for statements, etc. Flow control Tips for using statements. The code is as follows:
Demo1.php
<?php $username = "chaoyv"; echo "His name is $username !"; $username2 = "吴者然"; echo "His name is $username2 ! "; echo "<br/>"; echo "His name is ".$username2."，阅谁问君诵，\n水落清香浮。"; echo "<br/>"; echo "His name is ".$username2."，阅谁问君诵，\t水落清香浮。"; echo 'His name is $username2 ! ';//无法解析 $username2 ?>
Demo2.php
<?php $a = 5; $b = 6; // $c = $a + $b; // echo $c; // $a += $b;//$a=$a+$b; // echo $a; // $a=++$b;//$b=$b+1 // echo $a; //7 // echo $b; //7 $a=$b++; echo $a; //6 echo $b; //7 ?>
Demo3.php
<?php // $a = 5; // $b = '5'; // //在网页上（真true）的体现是1，假的体现是空 // //恒等必须数据类型也一样 // //$a === $b 返回的是一个假，false // echo !($a===$b); //这个会打印出什么呢？ $a = 5; $b = 5; $c = ($a ==$b); //echo $c; $d = 8; $e = 7; $f = ($d ==$e); //echo $c&&$f; echo $c||$f; ?>
Demo4.php
<?php $total = 80; //三元运算符 //如果判断为真true,那么整体返回第一个字符串，否则返回第二个字符串 $sum = $total>50?'成功':'失败'; echo $sum; ?>
Demo5.php
<?php //在开发过程中，最好将错误都暴露出来。 //$a = 100/0; Warning: pision by zero in C:\AppServ\www\Basic3\Demo5.php on line 2 $a = @(100/0); echo $a; ?>
Demo6.php
<?php
//if 条件判断语句
$userAge = 25;
//if 后面的括号是布尔表达式，返回的结果是1或者空
//{}块语句
// if($userAge>18){
// echo '成功';
// }
//如果。。。否则
// if($userAge>18){
// echo '成功';
// }else{
// echo '失败';
// }
//多重线路
if($userAge<18){
echo '<18';
}elseif ($userAge<30){
echo '<25';
}else{
echo '通过';
}
?>Demo7.php
<?php
//多重线路
//break退出问题，叫做中途退出这个条件判断
$weekday = 3;
switch ($weekday){
case 1:
echo '今天星期一';
break;
case 2:
echo '今天星期二';
break;
case 3:
echo '今天星期三';
break;
case 4:
echo '今天星期四';
break;
default:
echo '不清楚';
}
?>Demo8.php
<?php
//while 循环
//当判断表达式为假的时候，退出循环
$a = 10;
while ($a > 0){
echo $a;
$a--;
echo '<br/>';
}
?>Demo9.php
<?php
//for
for($a=10;$a>0;$a--){
echo $a;
echo '<br/>';
}
?>Demo10.php
<?php
//do while
$a = 10;
do{
echo $a;
echo '<br/>';
$a--;
}while($a>0);
?>Demo11.php
<?php
// for($i = 0;$i<10;$i++){
// //在这个循环里面嵌套一个 IF 判断语句
// if($i==5){
// break;//中途退出循环
// }
// echo $i.'<br/>';
// }
// for($i = 0;$i<10;$i++){
// //在这个循环里面嵌套一个 IF 判断语句
// if($i==5){
// exit;//退出整个程序
// }
// echo $i.'<br/>';
// }
// echo '我还会执行的';
for($i = 0;$i<10;$i++){
//在这个循环里面嵌套一个 IF 判断语句
if($i==5){
continue;//退出当前本次循环，并且继续下次循环 OK
}
echo $i.'<br/>';
}
?>The above is the detailed content of PHP basic operators and control structure process code examples. For more information, please follow other related articles on the PHP Chinese website!
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