I'm writing basically my first program for school. I've written small ones, following instructions, but this is the most vague. I'm having issues. I can't figure out what the error means. I'm not done with the code, but I think the ArrayList is throwing me off. I'm trying to gather user input and sum the total. Here's the code:
package graduationplanner;
import java.util.ArrayList;
import java.util.Scanner;
import java.lang.Double;
public class GraduationPlanner {
public static void main(String[] args) {
I am having issues with the program below everything works but I can't figure out a way to add code that if a user just hits enter without inputting anything it says "entering in nothing is not a valid choice" I am stuck on how to compare a int to a string ...
//import statements import java.util.*; //for scanner class // class beginning public class Guess { public static void main(String[] args ) { //Declare variables area
I made a guess a number program but I am having issue figuring out a way that when a user enter's in nothing for the program to spit out a message saying "hey entering nothing doesn't work try again" then ask for input. I have done some research and from what I have found is to read the input in as a String rather than int, and use something like Integer.valueOf() to get the integer value but I am completely lost on how to apply that to my program here is my code
//import statements import java.util.*; //for scanner class // class beginning public class Guess { public static void main(String[] args ) { //Declare variables area int guess, secretNumber = (int) (Math.random() * 10 + 1), lowGuess,highGuess;
I've been beavering away with Java for a few months. But as with all languages the String implementation looks designed to trip up even experienced programmers.
My current development gets data from various sources outside my control. When I get a string I want to test if it is empty/null/or whatever. Simple enough one thinks.
But if you search the internet you see everone seems to have a slightly different approach. So what is the best way of determining that a string is not useful to you?
I've had success with this
if(string == null || string.length() == 0)
But I've seen people using methods - not necessarily of String (e.g equals, empty) and regular expressions.
What is the best approach to this considering coding efficiency and/or processing efficiency (accepting you'd have to be processing a lot of strings for the latter to be an issue).
programming altogether and after almost reaching half way in the 'Head first java' book I decided to try and apply some of what I've learnt so far and write my first 'Object orientated' program. As this is pretty much the first program I've ever written, I decided to write a program to ask for two integers and add them both together and then present them to the user (the goal eventually being a basic fully working command line calculator with +,-,* and /. I'm expecting many compile errors but not the following errors below.
I have three .java files contained within a folder and after trying to figure out how to compile all three files (as they use one another) all at once, I came across this ---> javac *.java
so I typed this in the command line whilst in the directory containing the three files assuming *.java is the best approach and then I receive the following errors:
inputOutput.java:10: error: cannot find symb c.addition() = intIn.nextInteger(); ^ symbol: variable c location: class inputOutput
I keep getting the error Admit.java:10 cannot find symbol
import java.util.*; public class Admit { public static void main(String[] args) { sayIntro(); Scanner console = new Scanner(System.in); System.out.println("Information for applicant #1:"); getScore(console); getGPA(console);
[Code] ....
The compiler then reads:
Admit.java:10: error: cannot find symbol score1(ACTScore, SATScore, GPAScore); ^ symbol: variable ACTScore location: class Admit Admit.java:10: error: cannot find symbol
I have a msg object that contains an ArrayList<Integer> collection. However, in order to send the elements in the array over the udp socket, it needs to be sent as a byte[] array. So why am I using ArrayList<Integer> over byte array in first place? Well when I receive data from socket from embedded c program, I need to get an unsigned representation of the data, and thus I need to store it in integers, since bytes in Java are unsigned and unsigned chars in c that are greater than 127 will yield incorrect values in java. But when I send an ack back over the socket, I need to send the data back as bytes. So I convert the ArrayList<Integer> to a byte array:
Java Code: byte[] data = msg.toByteArray(); DatagramPacket response = new DatagramPacket(data, data.length, packet.getAddress(), packet.getPort()); public class Gprs { ... public byte[] toByteArray(){
[Code] ....
The problem is I get an "Cannot cast from Integer to byte" when trying to cast the integer to byte: data[i] = (byte)m_data.get(i);
I have the code below that just keeps getting the user's name and displaying it until the user enter's an empty string. Well, to simulate that, I just hit the keyboard instead of entering any name but for some reasons I am not seeing in my code, the programme just keeps looping.
System.out.println("Enter your name : "); Scanner st = new Scanner(System.in); while(st.hasNext()){ System.out.println("Enter your name : "); String name = st.nextLine(); System.out.println(name); if(name==" ") break; } System.out.println("you are out of the while loop now!!");
This is likely a simple matter, but my error is confusing given the line it flags matches a working project I have. I get the following error on line 6 in the Controller:
cannot find symbol v.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); ...........................................^ (carrot at the J)
My view file:
import java.awt.*; import javax.swing.*; import java.awt.event.*; public class View extends JFrame{ private JLabel lbl; private JButton btn;
This method accepts 1 integer, amount (the amount of money). Output the minimum number of in quarters, dimes, nickels and pennies used to make up the amount. For example, an amount of 32 would require 1 quarter, 1 nickel and 2 pennies.
This is the question^
My codes are:
public static int change (int amount) { int quarters = amount / 25 ; int firstresult = amount % 25 ; return quarters ; int nickel = firstresult / 5 ;
[Code] .....
The codes were working when i used System.out.println instead of return, but our teacher required us to use return (functions).
I have an empty string and I want to add to it crosses and naughts. I want to simulate a board of TicTacToe game. My goal is print out 5 strings like this : "xox xxx oxo". There are 3 groups of symbols separated with a space. The crosses and naughts are filled randomly.
Random rand = new Random(); char[] characters = new char[] { 'x', 'o' }; int numOfTimes = 0; while (numOfTimes < 5) { String board = ""; String space = " "; for (int group = 0; group < 3 ; group++)
Netbeans do not detect any syntax errors, but I when I check the build it retuned areas they were a few; It's a simple program name 5 people, gade them then do final calulatoins it's called "grade tool.
heres the code
package gradingapplication; import java.util.Scanner; public class GradingApplication { public static double score(double score){ if(score >= 90){ System.out.println("A");
[code]...
~Problems~
1. It has no gui, I don't know java fx, is java groove used? awt is useful for creating spam bots in robot class, I know it's not very useful but it's so much fun.
class SubB{ public void foo(){ System.out.println(" x"); } } public class X extends SubB { public void foo() throws RuntimeException{ super.foo(); if(true) throw new RuntimeException(); System.out.println(" B"); } public static void main(String [] args){ new X().foo(); } }
Why the foo method of class X is not throwing a compile error because according to the override rule, if the superclass method has not declared exception, the subclass method can't declare a new exception...
The project is a program that allows the user to enter students and enter grades for each student. One of the requirements is that if there is already a grade stored for the student that it will display the previous grade. IF the user then enters a new grade the new grade will be stored. IF the user simply presses enter (enters an empty string) nothing is done. I have everything working except for the requirement of doing nothing if the user enters an empty string. If I just press enter at this point I get a NumberFormatException.
The below code is a method "setTestGrades" from the student class. This method iterates through each student object stored in an array list and then checks if there is a previous grade (Requirement# unset grades have to default to -1) before allowing the user to set a new grade.
public void setTestGrades(int testNumber) { //Sets the grade for the specified test number for each student in the arraylist. testNumber -= 1; Scanner input = new Scanner(System.in); for (int i = 0; i < studentList.size(); i++) { System.out.println("Please enter the grade for Test #" + (testNumber + 1) + " For Student " + studentList.get(i).getStudentName());
I have a code in which I am reading input from System.in and Destination is some where else
Here is my code
File file=new File("D:/output.txt"); OutputStream os=new java.io.FileOutputStream(file); Scanner scanner=new Scanner(System.in); System.out.println("Enter Data to write on File"); String text=scanner.nextLine(); int c=Integer.parseInt(text); int a; while((a=c.read())!=-1) os.write(a); System.out.println("File Written is Successful");
In the line while((a=c.read())!=-1)
a compile time error is shown "cannot invoke read on primitive data type int"
I decided to code this quiz I took in class about asking the user to input a string and the code is suppose to check for upper case letters. If a upper case letter is found, it should increase a count by one. Once the check is done, it should display the number of uppercase letters. For some reason I am getting this weird compile error stating that symbols can't be found...
Java Code:
import java.util.*; import java.lang.*; public class StringCheck{ public static void main(String[] args){ Scanner input = new Scanner(System.in); System.out.println("please enter a string: " ); String s = input.nextLine();
public class op{ String word = "Hello"; //my variable public void reverseword() //My function { for(int i =word.length();i>=0 ;i--) { System.out.println(word.charAt(i));
[code]....
when i call function in main i have this error:
run: Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 5 at java.lang.String.charAt(String.java:658) at javacourse.Car.opname(Car.java:35) at javacourse.JavaCourse.main(JavaCourse.java:24) Java Result: 1
I am currently trying to split the string "EAM est" between the part. I have gotten the code to work if the was a -. But I can't see why the error is occuring
I have this error that keeps coming up any time I select one of my buttons. It actually doesn't hinder the performance of the project, everything works. But I am concerned I missed something and errors are never a good sign.On a slightly different note, I would like to figure out what the best way to format my output would be? I would like it to display as "100.00 F". I have a couple ideas on how to get the F symbol (or other symbol) by inserting something like
String degreesymbol = "F" or whichever it is and then returning that in the output string later. I can't get the decimal formatted correctly and I don't know how to print the degree symbol.Here is the code
