php控制语句

1. if语句

$a = 2;
$b = 1;
if($a>$b){
    echo "a大于b";
}

输出：a大于b

2.if...else语句

$a = 1;
$b = 2;
if($a>$b){
    echo "a大于b";
}else{
    echo "a不大于b";
}

3. if...elseif....else

$a = 1;
$b = 1;
if($a>$b){
    echo "a大于b";
}elseif($a<$b){
    echo "a小于b";
}else{
    echo "a等于b";
}

输出:a等于b

3. switch语句

$a = 6;
switch ($a){
    case 5;
        echo '555';
        break;
    case 4;
        echo '444';
        break;
    case 6;
        echo '666';
        break;
    case 7;
        echo '777';
}

输出：666