Switch Statement in Java

A switch statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each case. Let us first see the syntax −

switch(expression) {
   case value :
   // Statements
   break; // optional

   case value :
   // Statements
   break; // optional

   // You can have any number of case statements.
   default : // Optional
   // Statements
}

Following are the rules that apply to a switch statement in Java −

• The variable used in a switch statement can only be integers, convertable integers (byte, short, char), strings and enums.

• You can have any number of case statements within a switch. Each case is followed by the value to be compared to and a colon.

• The value for a case must be the same data type as the variable in the switch and it must be a constant or a literal.

• When the variable being switched on is equal to a case, the statements following that case will execute until a break statement is reached.

• When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the switch statement.

• Not every case needs to contain a break. If no break appears, the flow of control will fall through to subsequent cases until a break is reached.

• A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used for performing a task when none of the cases is true. No break is needed in the default case.

Let us now see an example −

Example

public class Demo {
   public static void main(String args[]) {
      char grade = 'B';
      switch(grade) {
         case 'A' :
            System.out.println("Excellent!");
            break;
         case 'B' :
         case 'C' :
            System.out.println("Well done");
            break;
         case 'D' :
            System.out.println("You passed");
         case 'F' :
            System.out.println("Better try again");
            break;
         default :
            System.out.println("Invalid grade");
      }
      System.out.println("Your grade is " + grade);
   }
}

Output

Well done
Your grade is B