Java Switch Statement

Switch statement in Java is for decision making. Unlike if-then and if-then-else statements, the switch statement can have a number of possible execution paths.

Syntax

The general form of a switch statement is:

switch (expression) { 
 case value1: 
 // statement sequence 
 break; 
 case value2: 
 // statement sequence 
 break;
 ... case valueN: 
 // statement sequence 
 break; 
 default: 
 // default statement sequence 
}

The expression must be of type byte, short, int, or char; each of the values specified in the case statements must be of a type compatible with the expression.

Note: From Java 7, String is also supported in expression.

Flow Chart

👁 Image

Figure: Switch Statement

Example

// An example to illustrate switch statement
class Switch {
 public static void main(String args[]) {
 int month = 4;
 String season;
 switch (month) {
 case 12:
 case 1:
 case 2:
 season = "Winter";
 break;
 case 3:
 case 4:
 case 5:
 season = "Spring";
 break;

 case 6:
 case 7:
 case 8:
 season = "Summer";
 break;
 case 9:
 case 10:
 case 11:
 season = "Autumn";
 break;
 default:
 season = "Bogus Month";
 }
 System.out.println("April is in the " + season + ".");
 }
}

The ouput of the program is:

April is in the Spring.

Here, expression month in switch statement matches to case with value 4, so season is assigned value Spring.

Note: three important features of the switch statement to be noted:

1. The switch differs from the if in that switch can only test for equality, whereas if can evaluate any type of Boolean expression. That is, the switch looks only for a match between the value of the expression and one of its case constants.
2. No two case constants in the same switch can have identical values. Of course, a switch statement and an enclosing outer switch can have case constants in common.
3. A switch statement is usually more efficient than a set of nested ifs.