How to Use the Switch Statement in Java

Have you ever found yourself in a situation where you needed to make a decision based on a specific condition in your Java code? If yes, then you must have used if-else statements in your code. But what if you had multiple conditions to check and make decisions based on each of them? This is where the switch statement in Java comes in handy.

The switch statement allows you to execute different blocks of code based on different conditions. It is a better alternative to using multiple if-else statements, especially when you have several conditions to check. In this article, we will discuss how to use the switch statement in Java.

What is a Switch Statement?

A switch statement is a control structure in Java that allows you to execute different code blocks based on different conditions. It is similar to the if-else statement but is more concise and readable when you have multiple conditions to check.

The switch statement evaluates a variable or an expression and compares it to each case label. If the value of the variable or expression matches a case label, the corresponding block of code is executed. If there is no match, the default block of code is executed.

Here is the syntax for a switch statement in Java:

switch (variable or expression) {
  case value1:
    // code block
    break;

  case value2:
    // code block
    break;

  case value3:
    // code block
    break;

  default:
    // default code block
    break;
}

The switch statement starts with the keyword switch, followed by the variable or expression that is being evaluated. Then, there are several case labels, each with a specific value. If the value of the variable or expression matches a case label, the corresponding code block is executed. The break keyword is used to indicate the end of each code block.

If none of the case labels match the value of the variable or expression, the default code block is executed. The default keyword is used to specify the default code block.

How to Use the Switch Statement in Java

Now that we understand what a switch statement is let’s dive into how to use it in Java. We will start with a simple example to illustrate the basic usage of the switch statement.

Let’s assume we have a variable dayOfWeek that stores the day of the week as an integer. We want to print a message depending on the day of the week. Here is how we can use the switch statement to achieve this:

int dayOfWeek = 3;

switch (dayOfWeek) {
  case 1:
    System.out.println("Today is Monday");
    break;

  case 2:
    System.out.println("Today is Tuesday");
    break;

  case 3:
    System.out.println("Today is Wednesday");
    break;

  case 4:
    System.out.println("Today is Thursday");
    break;

  case 5:
    System.out.println("Today is Friday");
    break;

  case 6:
    System.out.println("Today is Saturday");
    break;

  case 7:
    System.out.println("Today is Sunday");
    break;

  default:
    System.out.println("Invalid day of the week");
}

In this example, we declare a variable dayOfWeek and assign it a value of 3, which corresponds to Wednesday. We then use the switch statement to check the value of dayOfWeek and execute the corresponding code block. Since the value of dayOfWeek is 3, the code block that prints "Today is Wednesday" is executed.

If the value of dayOfWeek was not between 1 and 7, the default code block would have been executed, which prints "Invalid day of the week".

Multiple Cases for a Single Block of Code

Sometimes, you may want to execute the same block of code for multiple cases. Instead of repeating the same code for each case, you can group them together by omitting the break keyword.

Here is an example to illustrate this:

int month = 1;

switch (month) {
  case 1:
  case 2:
  case 3:
    System.out.println("Winter");
    break;

  case 4:
  case 5:
  case 6:
    System.out.println("Spring");
    break;

  case 7:
  case 8:
  case 9:
    System.out.println("Summer");
    break;

  case 10:
  case 11:
  case 12:
    System.out.println("Fall");
    break;

  default:
    System.out.println("Invalid month");
}

In this example, we declare a variable month and assign it a value of 1, which corresponds to January. We then use the switch statement to check the value of month and execute the corresponding code block. Since the value of month is 1, 2, or 3, the code block that prints "Winter" is executed.

Notice that we omitted the break keyword for the cases that correspond to the same block of code. This allows us to group them together and avoid repeating the same code.

Using Enumerations with Switch Statement

Java enumerations (enums) are a type-safe and more readable way of representing a fixed set of constants. You can use enums with the switch statement to make your code more concise and readable.

Here is an example to illustrate this:

enum DayOfWeek {
  MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY
}

DayOfWeek dayOfWeek = DayOfWeek.WEDNESDAY;

switch (dayOfWeek) {
  case MONDAY:
    System.out.println("Today is Monday");
    break;

  case TUESDAY:
    System.out.println("Today is Tuesday");
    break;

  case WEDNESDAY:
    System.out.println("Today is Wednesday");
    break;

  case THURSDAY:
    System.out.println("Today is Thursday");
    break;

  case FRIDAY:
    System.out.println("Today is Friday");
    break;

  case SATURDAY:
    System.out.println("Today is Saturday");
    break;

  case SUNDAY:
    System.out.println("Today is Sunday");
    break;
}

In this example, we declare an enum DayOfWeek that represents the seven days of the week. We then declare a variable dayOfWeek of type DayOfWeek and assign it a value of DayOfWeek.WEDNESDAY. We use the switch statement to check the value of dayOfWeek and execute the corresponding code block.

Notice that we don’t have to use integers to represent the days of the week, and our code is more readable and self-documenting.

Conclusion

In conclusion, the switch statement is a powerful control structure in Java that allows you to execute different blocks of code based on different conditions. It is a better alternative to using multiple if-else statements, especially when you have several conditions to check.

In this article, we have discussed how to use the switch statement in Java. We have seen examples of using multiple cases for a single block of code, and using enums with the switch statement to make your code more concise and readable.

As you continue to write Java code, consider using the switch statement where appropriate to make your code more readable and maintainable.

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