switch范围判断

 1 <?php
 2 function grade($grade){
 3     switch (true) {
 4         case $grade>=90:
 5             echo 'A';
 6             break;
 7         case $grade>=80:
 8             echo 'B';
 9             break;
10         case $grade>=70:
11             echo 'C';
12             break;
13         case $grade>=60:
14             echo 'D';
15             break;
16         default:
17             echo 'E';
18             break;
19     }
20 
21 }
22 grade(95);
23 grade(85);
24 grade(75);
25 grade(65);
26 grade(55);
27 
28 //ABCDE
29 ?>