AlphaCodingSkills

Java - Switch


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The Switch statement is used to execute one of many code statements. It can be considered as group of If-else statements.

Syntax


switch (expression){
  case 1:
     statement 1;
     break;
  case 2:
     statement 2;
     break;
     ...
     ...
     ...
  case N:
     statement N;
     break;
  default:
     default statement;
} 

The switch expression is evaluated and matched with the cases. When the case matches, the following block of code is executed.

Flow Diagram:

Java Switch

Example:

In the below example, the switch expression is a variable called i with value 2 which is matched against case values. When the case value matches with expression value, the following block of code is executed.

public class MyClass {
  public static void main(String[] args) {
    int i = 2;
    switch(i){
      case 1: 
         System.out.println("Red");
         break; 
      case 2: 
         System.out.println("Blue");
         break;
      case 3: 
         System.out.println("Green");
         break;
    }  
  }
}

Output

Blue

default and break statements

Default case and break statement are optional here.

  • Default Case: Default Statement is executed when there is no match between switch expression and test cases.
  • Break Statement: Break statement is used to get out of the Switch statement after a match is found.

Example:

In the below example, the switch expression is a variable called i with value 10 which is matched against case values. When the case value matches with expression value, the following block of code is executed and there is no case with value 10, hence default block of code is executed.

public class MyClass {
  public static void main(String[] args) {
    int i = 10;
    switch(i){
      case 1: 
         System.out.println("Red");
         break; 
      case 2: 
         System.out.println("Blue");
         break;
      case 3: 
         System.out.println("Green");
         break;
      default:
         System.out.println("There is no match in the switch statement.");
    }  
  }
}

Output

There is no match in the switch statement.

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