Could you please explain switch statement in Java

Question

Switch Statement Java

switch statement java

Java - parseInt() Method

Description

This method is used to get the primitive data type of a certain String. parseXxx() is a static method and can have one argument or two.

Syntax

Following are all the variants of this method −

static int parseInt(String s)

static int parseInt(String s, int radix)

Parameters

Here is the detail of parameters −

s − This is a string representation of decimal.

radix − This would be used to convert String s into integer.

Return Value

parseInt(String s) − This returns an integer (decimal only).

parseInt(int i) − This returns an integer, given a string representation of decimal, binary, octal, or hexadecimal (radix equals 10, 2, 8, or 16 respectively) numbers as input.

Example

Live Demo

public class Test { 

   public static void main(String args[]) {

      int x =Integer.parseInt("9");

      double c = Double.parseDouble("5");

      int b = Integer.parseInt("444",16);

      System.out.println(x);

      System.out.println(c);

      System.out.println(b);

   }

}

This will produce the following result −

Output

9

5.0

1092

Answer 1

switch statement in java

A switch statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each case.

Syntax

The syntax of enhanced for loop is −

switch(expression) {

   case value :

      // Statements

      break; // optional

   

   case value :

      // Statements

      break; // optional

   

   // You can have any number of case statements.

   default : // Optional

      // Statements

}

The following rules apply to a switch statement −

The variable used in a switch statement can only be integers, convertable integers (byte, short, char), strings and enums.

You can have any number of case statements within a switch. Each case is followed by the value to be compared to and a colon.

The value for a case must be the same data type as the variable in the switch and it must be a constant or a literal.

When the variable being switched on is equal to a case, the statements following that case will execute until a break statement is reached.

When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the switch statement.

Not every case needs to contain a break. If no break appears, the flow of control will fall through to subsequent cases until a break is reached.

A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used for performing a task when none of the cases is true. No break is needed in the default case.

Flow Diagram

Switch Statement

Example

public class Test {

   public static void main(String args[]) {

      // char grade = args[0].charAt(0);

      char grade = 'C';

      switch(grade) {

         case 'A' :

            System.out.println("Excellent!");

            break;

         case 'B' :

         case 'C' :

            System.out.println("Well done");

            break;

         case 'D' :

            System.out.println("You passed");

         case 'F' :

            System.out.println("Better try again");

            break;

         default :

            System.out.println("Invalid grade");

      }

      System.out.println("Your grade is " + grade);

   }

}

Compile and run the above program using various command line arguments. This will produce the following result −

Output

Well done

Your grade is C