Using a Switch for Days of the Week

The switch statement is a useful selection statement when there are many values that require different logic.

Here is a program that asks the user to enter a day number (1-7) and outputs the full name of that day of the week.

First, import the Scanner class (for user input), declare the class name, and declare the main method:

import java.util.Scanner;
public class Days {
  public static void main(String[] args) {

Next, declare a Scanner variable and create the object. This object will retrieve user input later:

    Scanner in = new Scanner(System.in);

Declare a variable to store the user input:

    int dayNum;

Ask the user to enter a number:

    System.out.print("Enter a day number (1-7): ");

Use the Scanner object to retrieve the user input. Note that the program will wait here until the user types a value and presses Enter:

    dayNum = in.nextInt();

Create a switch statement that switches on the dayNum variable:

    switch(dayNum) {

Inside the switch statement, add cases for each day. For example, the value 1 will output Monday:

      case 1:
        System.out.println("Monday");
        break;

Here are the other cases. Note that case 5 also outputs TGIF:

      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");
        System.out.println("TGIF!");
        break;
      case 6:
        System.out.println("Saturday");
        break;
      case 7:
        System.out.println("Sunday");
        break;  

The last case is a default case. This case occurs when the dayNum value has a number outside the range 1-7:

      default:
        System.out.println("Invalid day number.");
        break;   

Finally, add the closing curly brackets for the switch statement, main method, and class:

    } 
  }
}

Here is the complete program:

import java.util.Scanner;
public class Days {
  public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int dayNum;
    System.out.print("Enter a day number (1-7): ");
    dayNum = in.nextInt();
    switch(dayNum) {
      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");
        System.out.println("TGIF!");
        break;
      case 6:
        System.out.println("Saturday");
        break;
      case 7:
        System.out.println("Sunday");
        break;       
      default:
        System.out.println("Invalid day number.");
        break;                      
    } 
  }
}

Thanks for reading. 😃

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