if转switch

1. if($a=="a") {
2. echo "a";
3. } elseif ($a == "b") {
4. echo "b";
5. } elseif ($a == "c") {
6. echo "c";
7. } else {
8. echo "d";
9. }

switch($a){

case "a":

　　echo "a";

case "b":

　　echo "b";

case "c":

　　echo "c";

case "d":

　　echo "d";

}