Categories: Java

switch Statement

Java provides a multiple-branch selection statement known as a switch. This selection statement successively tests the value of an expression against a list of integer or character constants.

When a match is found, the statements associated with that constant are executed.

Syntax:

The syntax of the switch statement is as follows:


switch(expression)
{    
case constant1:    
    //statement sequence 1;    
    break;  //optional  
case value2:    
                     
    //statement sequence 1;    
    break;  //optional 
   
......    
......
......
......
Case value n:
                     
    //statement sequence 1;    
    break;  //optional   

default:     
 code for execution when none of the case is true;    
}    
 
  • The expression is evaluated, and its values are matched against the values of the constants specified in the case statements.
  • When a match is found, the statement sequence associated with that case is executed until the break statement or the end of the switch statement is reached.
  • The default statement gets executed when no match is found.
  • If the control flows to the next case below the matching case, in the absence of a break, this is called the fall-through condition.
  • The default statement is optional and, if it is missing, no action takes place if all matches fail.

Important: The data type of expression in a switch must be byte, char, short, or int.

Data Flow diagram for the switch:
Example:
// Online Java Compiler
// Use this editor to write, compile and run your Java code online
import java.util.*;
class HelloWorld {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
       int d;
       String ans;
        System.out.println("enter week day number: ");
        d=sc.nextInt();
        switch(d){
            case 1: ans="Sunday";
                     break;
            case 2: ans="Monday";
                     break;    
             case 3: ans="Tuesday";
                     break;      
             case 4: ans="Wednesday";
                     break;        
             case 5: ans="Thursday";
                     break;
              case 6: ans="Friday";
                     break;
             case 7: ans="Saturday";
                     break;       
            default: ans="INvalid day";         
                     
        }
        System.out.println("Day :"+ans);
    }
}
Output:
enter week day number: 6
Day :Friday

Note: also read about the if-else ladder & nested if block

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Published by
Rabecca Fatima

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