Java Switch statement

Switch Keyword:

The switch is one of the alternatives for the many if.....else conditions. Instead of using many if-else statements we case use the switch statements.

The main use of the switch statement It selects one of many code blocks to be executed.

//syntax for the java switch statement
switch(expression) {
  case a:
    // code block
    break;
  case b:
    // code block
    break;
  default:
    // code block
}

Important points :

• The switch statement can be evaluated one time only.

• The value of the expression is compared with the values of each case.

• If any match is found with the case then the specific code block will be executed.

• If we use the switch statement, we need to provide the default case value as well.

Switch Example:

public class Main{
    public static void main(String[] args){
        int number = 4;
        switch(number){
            case 1:
                System.out.println("Monday");
                break;
            case 2:
                System.out.println("Tuesday");
                break;
            case 3:
                System.out.println("Wednesday");
                break;
            case 4:
                System.out.println("Thursday");
                break;
            case 5:
                System.out.println("Friday");
                break;
            case 6:
                System.out.println("Saturday");
                break;
            case 7:
                System.out.println("Sunday");
                break;
            default:
                System.out.println("You have given an invalid entry");

        }
    }
}

Output:

Break Keyword:

The break is the keyword that can help helpful for breaking out of the switch statement.

The main use of this break keyword is, it will stop the execution of more code and case testing inside the block.

If a job is done, then the next step is to break from the switch. There is no need for extra testing.

public class Main{
    public static void main(String[] args){
        int age = 18;
        switch(age){
            case 18:
                System.out.println("Your Minor");
                break;
            case 19:
                System.out.println("You are Major");
                break;
            default:
                System.out.println("--Invalid--");
        }
    }
}

Output:

Default Keyword:

default is a keyword that is used in the Switch statements.

We need to provide the default case because even if all the switch cases fail then the default case code block gets executed.

public class Main{
    public static void main(String[] args){
        int age = 24;
        switch(age){
            case 18:
                System.out.println("Your Minor");
                break;
            case 19:
                System.out.println("You are Major");
                break;
            default: //here age is 24 and which is not matched with any case
                System.out.println("Age is above 25");
        }
    }
}