PHP : explication détaillée d'exemples simples d'utilisation de l'instruction switch

switch (expression)
{
case label1:
 code to be executed if expression = label1;
 break;
case label2:
 code to be executed if expression = label2;
 break;
default:
 code to be executed
 if expression is different from both label1 and label2;
}

switch($i){
  case 1:
    echo 1;
    break;
  case 2:
    echo 2;
    break;
  default:
    echo 'others';
}

<?php
header("content-type:text/html;charset=utf8");
$score=50;
switch($score)
{
 case $score>=90 && $score<=100:
  echo "优<br>";
  break;
 case $score>=80 && $score<90:
  echo "良<br>";
  break;
 case $score>=70 && $score<80:
  echo "中<br>";
  break;
 case $score>=60 && $score<70:
  echo "及格<br>";
  break;
 case $score>=0 && $score<60:
  echo "不及格<br>";
  break;
 default:
  echo"成绩输入错误<br>";
}
?>

<?php
switch ($x) {
  case 0:
  echo "x 等于 0";
  break;
  case 1:
  echo "x 等于 1";
  break;
  case 2:
  echo "x 等于 2";
  break;
  default:
  echo "x 既不等于1和2，也不等于0";
}
?>