Give me a break.
We will get to those other rules shortly. Here is the previous example, with more explanation:
double discount;
// Usually code would be read in
char   code = 'B' ;   
switch ( code )
{
  case 'A':
    discount = 0.0;
    break;
  case 'B':
    discount = 0.1;
    break;
  case 'C':
    discount = 0.2;
    break;
  default:
    discount = 0.3;
}
System.out.println( "discount is: " 
  + discount );
integerExpression is evaluated.
    code,
            which evaluates to the character 'B'.case 'B'statementList starts executing.
    discount.break statement is encountered.switch statment is executed.
    println() statementIf code is 'W' what is discount?