java.util.scanner

This question already has an answer here: How to use Scanner to accept only valid int as input 6 answers My program should ask user to enter the amount they want to withdraw from their account and calculating the current balance after withdrawing. The requirement for withdrawing is minimum 100 and maximum 1000. If the user enters wrong input the program should re-promt and ask user to enter amount again. This process will keep repeating until the user puts right amount. Once the right amount is choosen it should calculate and display the current balance. This is how I tried, but I failed to

I am trying to edit a matlabfile and replace some of the coding parts init in some specific lines. However, using the format below to make the changes it wont change the line context at all. (it will print the same old line). Any idea what am I doing wrong? 'replaceAll' is not suitable to replace some words with some others in the lines? Thanks in advance. try { PrintWriter out = new PrintWriter(new FileWriter(filenew, true)); Scanner scanner = new Scanner(file); while (scanner.hasNextLine()) { String line = scanner.nextLine(); if (line.contains("stream.Values(strmatch('Test',stream.Components

I'm trying to make a Connect Four Game in Java by using user input and drawing panel. Two people switch off turns typing the column they want their piece to go in. I'm having trouble making it so discs already placed stay on the board the next turn (because the a new drawing panel pops up with the updated board each time)(we tried using GUI but failed). I am also having trouble switching off turns and making the color change each time. Thank you so much, here is what I have so far. import java.util.*; import java.awt.*; public class ConnectFour{ public static void main(String[] args){ Scanner

I am making a voting system where the user logs in with their student number and makes a selection. Once someone has voted, they cannot be able to log in again. I made an object; Students, containing a String for the student number and a boolean for whether or not that student number has already voted (both being private). I made a dynamic array of this type as to accept a given amount of students off of a text file that is read through the use of a Scanner. However, when I try to populate the student number string within the object array, I get a NullPointerException. The Scanner IS reading

I am using the Scanner methods nextInt() and nextLine() for reading input. It looks like this: System.out.println("Enter numerical value"); int option; option = input.nextInt(); // Read numerical value from input System.out.println("Enter 1st string"); String string1 = input.nextLine(); // Read 1st string (this is skipped) System.out.println("Enter 2nd string"); String string2 = input.nextLine(); // Read 2nd string (this appears right after reading numerical value) The problem is that after entering the numerical value, the first input.nextLine() is skipped and the second input.nextLine() is

I'm suppose to enter 2 numbers, one int that is the amount to withdraw and one double which is the balance (with a space between them). Since every withdraw charges a fee of 0.5, balance must be a double. And thats what must be printed. I get error at nextDouble, why? I have just 1 month coding, I thought this was going to be a piece of cake, I think BASIC syntax ruined me 30 years ago :( import java.util.Scanner; public class Test { public static void main(String[] args) { //init variables int amount; double balance; //insert amount and balance Scanner input = new Scanner (System.in); amount

This question already has an answer here: How to get the separate digits of an int number? 26 answers I just started learning Java (two months and counting), and I still have lots of questions and a whole lot to learn. Right now I want to use the Scanner class to "divide" an integer into its digits. I'll explain myself better with an example: I request the user to type a four-digit integer, say 8919 . What I want to do is to use the Scanner class to divide that integer and to assign each one of its digits to a variable; i.e. a = 8 , b = 9 , c = 1 and d = 9 . I positively know that it can be