php流程控制

php流程控制

php if语句

• if语句
• if...elss语句
• if...else if...else语句
• switch语句

类似于其他语言

    $x=10;
    $y=50;
    if($x>$y)
        echo "$x 大于$y";
    else
        echo "$x 小于$y";
    echo "<br>";
    if($x>=90){
        echo "A";
    }
    else if($x>=80){
        echo "B";
    }
    else if($x>=60){
        echo "C";
    }
    else
        echo "D";

switch

        $grade="D";
        switch($grade){
            case "A":
                echo "优秀";
                break;
            case "B":
                echo "良好";
                break;
            case "C":
                echo "及格";
                break;
            default :
                echo "数据有误";
        }

php 循环

• while
• do...while

    $x=5;
    $y=5;
    while($x<5){
        echo $x."<br>";
        $x++;
    }
    echo "<br>";
    do{
        echo $y."<br>";
        $y++;
    }while($y<5);

• for

    for($x=0;$x<10;$x++){
        echo $x." ";
    }

• foreach

php foreach只适用于数组

        $arr=array("I","love","php.");

        foreach ($arr as $i){
            echo "$i ";
        }

换汤不换药