java.util.scanner

I want to capture enter character in console. I am inputting 2 strings. Case 1. removestudent(pressing enter) removes all the students from array list. Case 2. removestudent student1 removes students1 from array list. Scanner in=new Scanner(); type_op=in.next(); param=in.next(); if (type_op.equals("removestudent")) { //Calling remove student function and passing param over here. } Now the case 2 works fine. However, for Case 1, I want param value to be null when user presses enter. I will then pass param as a null value to my remove function and delete all the students in the array list. list1

Using try(Scanner scan = new Scanner(System.in)) { } is causing Exception in thread "main" java.util.NoSuchElementException When I try to debug it says that Variable information not available, source compiled without -g option. and shows the below code public Scanner(InputStream source) { this(new InputStreamReader(source), WHITESPACE_PATTERN); } One of my methods that uses this line: protected String loginName(){ String username; String password; try (Scanner scan = new Scanner(System.in)) { // This line is causing the error. System.out.print("Enter Username: "); username = scan.next();

I have text file called BookingDetails.txt inside the file there's a line of records Abid Akmal 18/11/2013 0122010875 Grooming Zalman 5 125.0 Dog It goes from First name: Abid, Last name: Akmal, Date, phone number, type of services, pet name, days of stay, cost, and type of pet. I want to create a user input function in which when the user enters the first name and the last name, the whole line is deleted. But note that it will only affect that particular line as they will be more booking entry in the text file. This is only a part of my program that I don't know how to do. I'm stuck here

If I run this code Scanner sc = new Scanner(); while (true) { if (sc.next().equals("1")) System.out.println("--1--"); else if (sc.next().equals("2")) System.out.println("--2--"); else if (sc.next().equals("3")) System.out.println("--3--"); else if (sc.next().equals("4")) System.out.println("--4--"); else if (sc.next().equals("help")) System.out.println("--help--"); } It will not read the first time I type enter. I have to type 2-4 times before it reads the input. A session could look like this: 1 1 1 1 --1-- 3 3 --3-- help 2 1 help --help-- No matter what I type, it will only read the last

I am using a while loop to make sure that the value entered to a scanner object is an integer as such: while (!capacityCheck) { try { System.out.println("Capacity"); capacity = scan.nextInt(); capacityCheck = true; } catch (InputMismatchException e) { System.out.println("Capacity must be an integer"); } } however, if the user does not enter an integer, when it should go back and take another input it just repeatedly prints "Capacity" followed by the output in the catch without asking for more input. How do I stop this? scan.nextLine(); Put this piece of code inside your catch block, to consume

import java.util.Scanner; public class Test{ public static void main(String[] args){ Scanner input = new Scanner(System.in); input.useDelimiter("."); String given = input.next(); System.out.println(given); } } When I run the above code and type in asdf. then enter, I get nothing. It works fine with "," ";" "\"" "\\\\" or whatever, but just not with "." ... So is there something about a dot or is it just a problem with Eclipse IDE or whatever? Scanner is using regular expression (regex) as delimiter and dot . in regex is special character which represents any character except line separators.

I'm using scanner to read a text file line by line but then how to get line number since scanner iterates through each input?My program is something like this: s = new Scanner(new BufferedReader(new FileReader("input.txt"))); while (s.hasNext()) { System.out.print(s.next()); This works fine but for example: 1,2,3 3,4,5 I want to know line number of it which mean 1,2,3 is in line 1 and 3,4,5 is in line 2.How do I get that? You could use a LineNumberReader in place of the BufferedReader to keep track of the line number while the scanner does its thing. LineNumberReader r = new LineNumberReader

In a single class I have two different methods who are using the scanner class. I created a new instance of scanner object for the first method, then closed it at the end of the first method...then created a new instance of an object (with a different name) in the second method to finally close it at the end of this method. Unless I open the scanner once and close it once it won't work and return an error. The double use of the scanner class doesn't seem to work. What am I doing wrong? Here are my two methods which return an error... public void GameSetup(){ //intro to the program and what the