MyStack class have by default some fixed size of maximum elements, allow user of your class to specify in constructor what this maximum size is. Also add possibility to specify name of the stack in constructor. User can either create object without parameters, can specify only size or name, or both of them. And also override function toString(), that this code will print:
I remember reading that a super() call to parent no-argument constructor is automatically inserted by compiler. So, if i have a chained hierarchy of classes (starting at top, with Object), will there be a chain of super() calls, going from bottom to top in the chain ? Will a super() call be inserted in child, if i provide a no-argument constructor for this class ?
class Test3 { } class MySub extends Test3 { } class Test4{ public static void main(String args[]) { MySub m = new MySub(); } }
I learned that if a class and its parent class both have no constructors, the compiler is supposed to complain. When I compiled Test4, i got no errors. why did it give no errors?
I have to create an application that deals with maps.
I first have to create the instance variables for the class.
So very simply if my hashmap is going to consist of football clubs and players. Football clubs being a string value for the key and players being a set of strings for the values. How would I go about creating the instance variable in a class for this?
I can't seem to find anything that specifically deals with instance variables and constructors for maps.
Write a class Month that represents one of the twelve months of the year. It should have three attributes for
the name of the month,
the number of days in the month, and
the birthstone.
Also add constructors and getter/setter methods to access the attributes.
You may use the following code to test your class.
Java Code:
import java.util.*; public class Month { // ADD CODE HERE!!! public static void main(String[] args) { Month[] months = new Month[12];
[Code] ....
So what I have added so far is (under public class month { :)
Java Code:
String monthName, monthBirthStone; int monthDays; public Month (String name, int days, String birthstone) { monthName = name; monthBirthStone=birthstone; monthDays=days; } mh_sh_highlight_all('java');
So I believe that is the constructor. I still do not understand several things:
What would I need the getter and setter for?
I tested it using just the above code, and using month 1 I got:
Month@5a1cfb56
This makes sense as I obviously didn't do anything in order to get it in a String format for the array. But I do not understand this still - how would I get the constructor to output a string (to then be in the array?)
We have to create a program called MyStack.In Push: Add one element at the end of the buffer.In Pull: Remove one element from the end of the buffer. In isEmpty: Should check if the list is empty or not and return the result as a boolean variable.
I am totally confused, I wrote the buffer and the array, but how do i add an remove element from the buffer?How do i add an element? What Statement do i Use?
Java Code: public class MyStack<T> implements Stack<T> { private final T[] ringbuffer; int index = 0; int last;
I am to create a Array class then create a Driver class (TestArray) to test all the methods in the Array Class. Here's the code i've written for the Array Class. I just nee developing the TestArray class.
import java.util.Scanner; public class Array { Scanner sc = new Scanner(System.in); private double[] array = new double[]; public void setArray(double[] arr) {
Prompt: Write a class encapsulating the concept of a circle, assuming a circle has the following attributes: a Point representing the center of the circle, and the radius of the circle, and integer.
Include a constructor, the accessors and mutators, and methods toString and equals. Also include methods returning the perimeter ( 2 x đťś‹ x đť‘ź ) and area ( đťś‹ x đť‘ź^2) of the circle. Write a client (application) class to test all the methods in your class. I started out trying to thing how to do this and I mapped out a certain idea but do not know how to incorporate the point represent the center of the circle. I am not sure how to proceed further..
import java.awt.*; public class Circle { Â public static void main(String[] args) { Â final double PI = 3.14; int x,y, radius = 4; double area; double perimeter; Â [Code] ...
I have an assignment to write a Payroll class that uses the following arrays as fields:
-employeeID - An array of seven integers to hold employee identification numbers. The array should be initialized with the following numbers: 5658845 4520125 7895122 8777541 8451277 1302850 7580489 -hours - An array of seven integers to hold the number of hours worked by each employee -payRate - An array of seven doubles to hold each employees hourly pay rate -wages - An array of seven doubles to hold each employees gross wages
The class should relate the data in each array through the subscripts. For example, the number in element 0 of the hours array should be the number of hours worked by the employee whose identification number is stored in element 0 of the employeeID array. That same employee's pay rate should be stored in element 0 of the payRate array. In addition to the appropriate accessor and mutator methods, the class should have a method that accepts an employee's identification number as an argument and returns the gross pay for that employee. Demonstrate the class in a complete program that displays each employee number and asks the user to enter that employee's hours and pay rate. It should then display each employee's identification number and gross wages. Input Validation: Do not accept negative values for hours or numbers less than 6.00 for pay rate.
I'm off to a great start, however I'm stumped on how to pass the payrate for each employee into the array, then grab that data in order to calculate the gross wage for each employee and store THAT in its own array. THEN I'll have to output that data to each employee.
Code is shown below.
import java.util.Scanner; import java.text.DecimalFormat; public class PayrollProgram { public static void main(String[] args) { Scanner userInput = new Scanner(System.in); DecimalFormat df = new DecimalFormat("0.00");
Write a class encapsualting the concept of a course grade, assuming a course grade has the following attributes: a course name and a letter grade. Include a constructor, the accessor and mutator, and methods toString and equals.Write a client class to test all the methods in your class.
package labmodule7num57; import java.util.*; public class LabModule7Num57 { // Constructors//
Write an instance method, contains, that has one explicit parameter of type Rectangle. The method should return true if every point of the rectangle determined by the explicit parameter is on or within the rectangle determined by the implicit parameter. It should return false otherwise.
I was wondering if I could write this code in one line.
import java.util.Scanner; public class Test { public static void main(String[] args) { Scanner sc = new Scanner(System.in); char ch = sc.next().charAt(0); } }
Can I combine "import java.util.Scanner","Scanner sc = new Scanner(System.in);" and "char ch = sc.next().charAt(0);" in one statement? The object created from the class Scanner may be anonymous but it doesn't concern me!
1. The words remain in their places but the letters are reversed. Eg I love you becomes Ievol uoy 2. The words are also reversed. Eg I love you becomes uoy evol IWrite a program that use the java String class methods.
Write a class that accepts a user's hourly rate of pay and the number of hours worked. Display the user's gross pay (gross pay = hours worked * hourly rate), the tax withheld (tax withheld = gross pay * tax rate) and the net pay (net pay = gross pay - tax withheld).Use a named constant for storing the tax rate of 0.15
Here is my Code: Â import java.util.Scanner; Â class Tutorial { public static void main(String[] args);
Is it possible to combine two classes that I have defined to contain some of the same elements so that NetBeans stops giving me errors? I don't want to get rid of any necessary code, and if both classes are necessary, should I just rename one of them? One class is an ArrayList that I am using to write the information for employees entered to a text file "employee.txt." I also want users to be able to call on this information via employeeID in order to display employee information. The code is the following:
public ArrayList<Employee> getEmployees() { // if the employees file has already been read, don't read it again if (employees != null) return employees; employees = new ArrayList<>(); if (Files.exists(employeesPath)) // prevent the FileNotFoundException {
[code]....
The other class is a getEmployee class that I previously defined before attempting to read the information from the text file and display it in the console. It is as follows:
private void getEmployees() { try { // if the file doesn't exists, create it if (!Files.exists(employeesPath)) Files.createFile(employeesPath); BufferedReader in = new BufferedReader( new FileReader(employeesFile));
I am getting error in second constructor that I have created, it gives an error: cannot find symbol variable
package Objects;
import javax.swing.JOptionPane; public class Constructor { public static void main(String[] args) { Piggybank1 pg1 = new Piggybank1("Abhinav", 500); pg1.deposit(200); pg1.withdraw(10);
We are learning about how to pass objects into constructors. In our class, we made this following code:
public class InventoryItem { //fields private String description; private int units; //Add New constructor public InventoryItem(InventoryItem some_object) { description=some_object.description;
[Code] .....
As you can see the object of the same class is passed as the argument. Inside the constructor, our teacher did
some_object.description
This constructor, from my understanding, copies the description field and unit field to an object to the new object of class. Meanwhile, here is the demo class.
public static void main(String[] args) { //Create object InventoryItem item1; item1=new InventoryItem("hammer",20); Â System.out.println("Item 1: ");
[Code] .....
Over here, my teacher uses :
.getDescription
My problem is that in the constructor of the first class I showed, why didn't he use
.getDescription
method instead of this
.description
May I know what is difference between these two. If I use .getdescription that would return the value of a field from that object too.
So while experimenting with constructors, repeating constructors with the same parameters, and with different parameters. I got an output -explaining how I got it.
I made 2 classes. a "support class" (has all the info) and an "execute class" (executes info).
Support:
package inschool; public class Constructors { String video; public Constructors() { video = "frozen";
[Code] ....
Execute:
package inschool; //this is part of Constructors class public class App{ public static void main(String[] args){
[Code] ....
The Output:
the video name is frozen Second constructor running Constructor running! the video name is frozen
Output Explanation:
constructor call number 1 and 3 are the same (essentially) and both refer to the same constructor.
My Question: if both call #1 and #3 refer to the same constructor, why is the output for #1 "the video name is frozen"
while the output for #3 used both methods in the accessed constructor-with the resulting output as "Constructor running!" and "the video name is frozen"
I double checked the output-and this time made sure to scroll up ... its the same result
public class Cash { //Quanity Field and RetailItem Object field private int total_units; private Retail myRetail; Â //Create first constructors public Cash() { this(0,null); Â [Code] ....
I'm seriously need to understand the concept of making shallow copies and deep copies. My book has shown me that its better to perform deep copies and I have followed that method. if you guys look in my constructor of the cash class
//Create a a constructor public Cash(int total_units,Retail myRetail) { this.total_units=total_units; this.myRetail=new Retail(myRetail);
Apparently I have field in Cash Class named
Retail myRetail
When I pass in an argument from my demo, I'm making a copy of that object from the demo class. In my retail class, I have the following copy constructor .
//Make a copy constructor public Retail(Retail Object1) { Item_Name=Object1.Item_Name; Item_Number=Object1.Item_Number; // if I use this then my program would work//this.cost=Object1.cost; Â //if I use this part of code below, my program won't work at all and I would get an error saying Exception in thread "main" java.lang.NullPointerException this.cost.Item_Cost=Object1.cost.Item_Cost; this.cost.Wholesale_Cost=Object1.cost.Wholesale_Cost; }
My question is why can't I perform a deep copy there. I know if I do
this.myRetail=myRetail
in my cash constructor it would work, but then the book says its not a good method;
In Java code, write class called Student with the following features:
• a private instance variable int studentNumber that is initialized to zero. • a private instance variable String firstName; • a private instance variable String lastName; • a constructor which takes an integer argument and two String arguments to initializes the three respective data items. • a public method with signature equals(Student s) . . .
So far this is my code :
public class student { private int studentnumber = 0; public student () { firstname= "forename": lastname="surname": public student (integer studentnumber, string firstname, string lastname) { this.firstname= firstname this.lastname= lastname:
My question is how do i add the integer in the argument do i have to use int =? and how would i go about doing the public signature equals...
