switch statement in while loop java

1// switch case in java example programs
2public class SwitchStatementExample
3{
4   public static void main(String[] args)
5   {
6      char grade = 'A';
7      switch(grade) {
8          case 'A' :
9              System.out.println("Distinction.");
10              break;
11          case 'B' :
12          case 'C' :
13              System.out.println("First class.");
14              break;
15          case 'D' :
16              System.out.println("You have passed.");
17          case 'F' :
18              System.out.println("Fail. Try again.");
19              break;
20          default :
21              System.out.println("Invalid grade");
22      }
23      System.out.println("Grade is: " + grade);
24   }
25}

1// syntax of switch statement in java
2switch(expression)
3{
4   case 1 value :
5   // code goes here
6   break;
7
8   case 2 value :
9   // code goes here
10   break;
11
12   case 3 value :
13   // code goes here
14   break;
15   .
16   .
17   .
18   .
19   
20   default: // optional
21   // default code goes here
22}

1Scanner input=new Scanner(System.in);
2int selection = input.nextInt();
3
4while (selection<4)
5{
6   switch(selection){
7        case 1:
8           System.out.println("Please enter amount");
9           double amount=input.nextDouble(); //object of scanner class
10           break;
11
12        case 2:
13           System.out.println("Enter ID number"); 
14           break;
15
16        case 3:
17           System.out.println("Enter amount to be credited");
18           break;
19      }
20      System.out.println("1. Transfer\n2.Check balance\n3.Recharge");
21      selection = input.nextInt(); // add this
22 }