The nextDouble() je metoda razreda Java Scanner, ki se uporablja za skeniranje naslednjega žetona vnosa kot dvojnika. Če je prevod uspešen, optični bralnik mimo vnosa, ki se ujema.

Sintaksa

Sledi izjava nextDouble() metoda:

 public double nextDouble() 

Parameter

Ta metoda ne sprejema nobenega parametra.

Vračila

The nextDouble() metoda vrne dvojno skenirano iz vnosa.

Izjeme

InputMismatchException - To izjemo bo sprožil, če se naslednji žeton ne ujema z regularnim izrazom Float ali je izven obsega.

NoSuchElementException - Če je vnos izčrpan, bo sprožil to izjemo.

regresijski izraz v Javi

IllegalStateException - To izjemo bo sprožil, če se bo priklic izvedel po zaprtju Scannerja.

Združljivostna različica

Java 1.5 in novejši

Primer 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(); } } 

Izhod:

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

Primer 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(); } } 

Izhod:

primer odprtokodnega operacijskega sistema je

 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 

Primer 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() } } 

Izhod:

 Enter value: 375437.565 Your entered Double value: 375437.565 

Primer 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 +' 
Twice value : ' + 2.0*value ); scan.close(); } } 

Izhod:

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