Java Scanner nextDouble() Method

The nextDouble() is a method of Java Scanner class which is used to scan the next token of the input as a double. If the translation is successful, the scanner past the input that matched.

Syntax

Following is the declaration of nextDouble() method:

Parameter

This method does not accept any parameter.

Returns

The nextDouble() method returns the double scanned from the input.

Exceptions

InputMismatchException- It will thrown this Exception if the next token does not match the Float regular expression, or is out of range.

NoSuchElementException- It will thrown this Exception if the input is exhausted.

IllegalStateException- It will thrown this Exception if the innvocation is done after Scanner is closed.

Compatibility Version

Java 1.5 and above

Example 1

import java.util.*;
public class ScannerNextDoubleExample1 {  
    public static void main(String args[]){   	
    	  int amount;
        double balance;
        //Insert amount and balance from console
        Scanner input = new Scanner (System.in);
        System.out.println("Enter the amount: ");
        amount = input.nextInt();
        System.out.println("Enter the Total Balance: ");
        balance = input.nextDouble();
        //reduce amount+fee from balance
        balance=balance-(amount + 0.50);
        //print new balance
        System.out.print("Left Balance is: "+balance);
        input.close();
	    }  
}

Output:

Enter the amount: 
213734
Enter the Total Balance: 
5684566.856
Left Balance is: 5470832.356

Example 2

import java.util.*;  
public class ScannerNextDoubleExample2 {  
     public static void main(String args[]){ 
    	   String str = "Hello World! 12 + 13.0 = 15 ";
         Float f = 2.123f;
         str = str + f;
         //Create a new scanner with string Object
         Scanner scanner = new Scanner(str);
         //Use US locale to be able to identify doubles in the string
         scanner.useLocale(Locale.US);
         //Find the next double token and print it
         while (scanner.hasNext()) {
            //Check if the next is a double, print found
            if (scanner.hasNextDouble()) {
               System.out.println("Found Double:" + scanner.nextDouble());
            }
            //If double is not found, print "Not Found"
            System.out.println("Not Found Double:" + scanner.next());
         }    
         scanner.close();
     }  
} 

Output:

Not Found Double:Hello
Not Found Double:World!
Found Double:12.0
Not Found Double:+
Found Double:13.0
Not Found Double:=
Found Double:15.0
Not Found Double:2.123

Example 3

import java.util.*;
public class ScannerNextDoubleExample3 {  
    public static void main(String args[]){   	
    	    Scanner scan = new Scanner(System.in);
    	    System.out.print("Enter value: ");  	    
    	    if(scan.hasNextDouble())
    	    {
    	      double y  = scan.nextDouble();
    	      System.out.println("Your entered Double value: " +y);
    	    }   	            
    	    else if (scan.hasNext())
    	    {
    	    	System.out.println("Please Entered the Double Value.");
    	      System.out.println("You entered: " + scan.next());
    	    }
    	    scan.close()
	    }  
}

Output:

Enter value: 375437.565
Your entered Double value: 375437.565

Example 4

import java.util.*;
public class ScannerNextDoubleExample4 {  
    public static void main(String args[]){   	
    	  double value;
        Scanner scan = new Scanner(System.in);     
        System.out.print("Enter the numeric value : ");
        value = scan.nextDouble();
        System.out.println("Double value : " + value +" \nTwice value : " + 2.0*value );
        scan.close();
	  }  
}

Output:

Enter the numeric value : 12345
Double value : 12345.0 
Twice value : 24690.0

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