分支结构

<?php
    // 分支结构
    // 单分支
    $age=18;
    if($age>=18){
        echo "你好";
    }else{
        echo "你几岁";
    }
    echo "<br>";
    // 多分支
    $age=10;
    if($age>=18&&$age<=65){
        echo "你好";
    }
    elseif($age<18){
        echo "你好小朋友";
    }
    elseif($age>65){
        echo "你好老人";
    }
    elseif($age>=110){
        echo "你好神仙";
    }
    else{
        echo"请输入正确年龄";
    }
    echo "<br>";
    // switch 
    $age = 100;
    switch(true){
        case $age>=18&&$age<=65:
            echo "你好";
            break;
        case $age<18:
            echo "你好小朋友";
            break;
        case $age>65:
            echo "你好老人";
            break;
        case $age>=110:
            echo "你好神仙";
            break;
        default:
            echo"请输入正确年龄";
    }

效果：

循环和混编

<?php
// 用二维数组来模拟数据表查询结果集
$stus = [
    ['id' => 1, 'name' => '刘备', 'course' => 'js', 'score' => 83],
    ['id' => 2, 'name' => '关羽', 'course' => 'php', 'score' => 75],
    ['id' => 3, 'name' => '张飞', 'course' => 'js', 'score' => 52],
    ['id' => 4, 'name' => '孙权', 'course' => 'php', 'score' => 88],
    ['id' => 5, 'name' => '周瑜', 'course' => 'js', 'score' => 65],
    ['id' => 6, 'name' => '孔明', 'course' => 'php', 'score' => 53],
    ['id' => 7, 'name' => '赵云', 'course' => 'js', 'score' => 63],
    ['id' => 8, 'name' => '马超', 'course' => 'js', 'score' => 77],
    ['id' => 9, 'name' => '姜维', 'course' => 'php', 'score' => 93],
    ['id' => 10, 'name' => '黄忠', 'course' => 'js', 'score' => 81],
]
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>遍历与混编</title>
    <style>
        table{
            border-collapse: collapse;
            width: 1000px;
            height: 500px;
            text-align: center;
            margin: auto;
        }
        table th,
        table td {
            border: 1px solid #000;
            padding: 5px;
        }
        table caption{
            font-size: 1.3em;
        }
        table thead{
            background-color: lightcyan;
        }
    </style>
</head>
<body>
    <table>
        <caption>学生成绩</caption>
        <thead>
           <tr>
               <th>ID</th>
               <th>姓名</th>
               <th>课程</th>
               <th>成绩</th>
           </tr>
        </thead>
        <tbody>
            <?php foreach($stus as $stu):?>
                <tr>
                    <td><?php echo $stu['id']?></td>
                    <td><?php echo $stu['name']?></td>
                    <td><?php echo $stu['course']?></td>
                    <td><?php echo $stu['score']?></td>
                </tr>
            <?php endforeach ?>
        </tbody>
    </table>
</body>
</html>

分支、循环、混编学习小结

分支结构

效果：

循环和混编

效果：