JavaScript: Do I require break statement in default case of switch statement

If you added default case at the end of all the switch cases, then you do not require a break statement.

HelloWorld.js

function print_day_of_week(day){
  switch(day){
    case 1:
      console.log("Sunday");
      break;
    case 2:
      console.log("Monday");
      break;
    case 3:
      console.log("Tuesday");
      break;
    case 4:
      console.log("Wednesday");
      break;
    case 5:
      console.log("Thursday");
      break;
    case 6:
      console.log("Friday");
      break;
    case 7:
      console.log("Saturday");
      break;
    default:
      console.log("Not a valid day");
  }
}

print_day_of_week(10);

Output

Not a valid day

But if you add default case anywhere not at the end, then you should add break statement.

HelloWorld.js

function print_day_of_week(day){
  switch(day){
    case 1:
      console.log("Sunday");
      break;
    case 2:
      console.log("Monday");
      break;
    default:
      console.log("Not a valid day");
    case 3:
      console.log("Tuesday");
      break;
    case 4:
      console.log("Wednesday");
      break;
    case 5:
      console.log("Thursday");
      break;
    case 6:
      console.log("Friday");
      break;
    case 7:
      console.log("Saturday");
      break;
  }
}

print_day_of_week(10);

As you see above snippet, I added default case after case 2 and do not provided break statement inside default case.

When I ran above application, I seen below two messages.

Not a valid day

Tuesday

It is because, break is omitted, the program continues execution at the next statement in the switch statement.

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Branching statement: continue

continue statement skips the current iteration of a for, while, do-while loops. Just like break, continue also has two forms.

    1. unlabelled continue

    2. labelled continue

Unlabelled continue

    Syntax

        continue;

Example: Count the number of odd values from 0 to 10

class ContinueEx{
 public static void main(String args[]){
  int counter = 0;
  
  for(int i=0; i < 11; i++){
   if(i % 2 == 0)
    continue;
   System.out.println(i);
   counter++;
  }
  
  System.out.println("Total number of odd numbers from 0 to 10 is " + counter);
 }
}

       

Output

1
3 
5
7
9  
Total number of odd numbers from 0 to 10 is 5 

       

Labelled continue

     Syntax

     continue labelName;

Example

class ContinueEx{
 public static void main(String args[]){
  int counter = 0;
  
  myLabel:
   for(int i=0; i < 11; i++){
    if( i < 10)
     continue myLabel;
    System.out.println(i);
   }
   
  System.out.println("I am out of the label");
 }
}

Output

10
I am out of the label

break statement                                                 arrays                                                 Home

Branching statement: break

The break Statement

We already seen the use of break in switch case. Similarly, break is used in while, do-while and for loops. Break has two forms in java.

   1. unlabelled break

   2. labelled break

unlabelled break

   Example

class BreakEx{
 public static void main(String args[]){
  for(int i=0; i < 10; i++){
   if(i==5) break;
   System.out.println(i);
  }
  System.out.println("I am out of the loop");
 }
}

Output

0
1
2
3
4
I am out of the loop

 

As you in the above program, when variable “i” reached to 5, break is called, and execution comes out of the loop

labelled break

   label is a group of statements, identified by using labelname.

Syntax

    labelName:{

      statement 1

      statement 2

      …....

      statement N

    }

Example

class BreakEx{
 public static void main(String args[]){
  myLoop: {
   for(int i=0; i < 10; i++){
    if(i==5) break myLoop;
    System.out.println(i);
   }
   System.out.println("I am also in label");
  }
  System.out.println("I am out of the loop"); 
 }
}

        

Output

0
1 
2
3
4 
I am out of the loop

 

As you see in the above program label name is myLoop. When variable 'i' value reaches to 5,  execution comes out of the label.

loops                                                 continue statement                                                 Home