What is a Switch Case Statement in Java and How to Use It

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.

Syntax

switch(expression) {
   case value :
      // Statements
      break;
   case value :
      // Statements
      break;
   // You can have any number of case statements.
   default :
      // Statements
}

The following rules apply to a switch statement −

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

Example

public class Test {
   public static void main(String args[]) {
      // char grade = args[0].charAt(0);
      char grade = 'C';
      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);
   }
}

Compile and run the above program using various command line arguments. This will produce the following result −

Output

Well done
Your grade is C