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I need to pass a variable into a method

In my code I created a class called Points which checks answer for given question and returns score. Another class called Report takes some information to prints it
package finalproject;
public class Points {
public static float calculatePoints(byte[] userAnswer) {
byte realAnswer[], gradeCounter;
float score ;
gradeCounter = 0;
realAnswer = new byte[3];
realAnswer[0] = 3;
realAnswer[1] = realAnswer[2] = 1;
for (int i = 0; i < userAnswer.length; i++) {
if (userAnswer[i] == realAnswer[i]) {
gradeCounter++;
}
}
score = (gradeCounter / 3) * 100;
return score;
}
}
package finalproject;
public class Report {
public static void getLoginInfo(String[] loginInformation) {
loginInformation = new String[2];
String name, id;
name = loginInformation[0];
id = loginInformation[1];
}
public static void printReport() {
System.out.println("\n\n-------------------\n\n");
System.out.println("\t\tJava Certification");
System.out.println("\t\t Test Result\n\n");
System.out.println("\tName: ");
System.out.println("\tTest Registration ID: ");
System.out.println("\tPassing Score 52%");
System.out.println("\tYour Score: ");
/*
* if (score1 >= 52.0) { System.out.println("\n\nComment GRADE: pass\n\n"); }
* else { System.out.println("\n\nComment GRADE: fail\n\n"); }
*/
System.out.println("Max Score\t" + "---------------100%");
System.out.println("Max Score\t" + "--------52%");
}
}
In getLoginInfo variable called name and id should be set and I want to pass them into printReport.
I want to pass variable called score in function calculatePoint() to printReport how can I do it ?

If you declare name and id outside any function the scope of strings name and id would be that of class meaning it will be visible to all functions in class Report. Each object/instance of class report will have name and id as attributes. Then getLoginInfo can be used to set and printReport() can be used to print name and id.
public class Report {
String name, id;
public static void getLoginInfo(String[] loginInformation){
name = loginInformation[0];
id = loginInformation[1];
}
public static void printReport() {
...
}
}

Java - Cannot display user input data as an output table using classes

UPDATE - Thanks for the suggestions. At least now my program runs without major errors.
When items stored reaches 3 sets of data, program terminates and displays output table. However, only the titles are displayed and wondering how I would fetch the user input data of each element, and display under each column column heading stored within ChessList.java but going through ChessMain.java (As like the table headings stored within ChessList.java)
Any suggestions. Thanks
ChessMain.java
import java.util.Scanner;
public class ChessMain {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
ChessList listOfNumbers = new ChessList("");
boolean finished = false;
for(int i = 0; i <2; i++) {
System.out.print("Enter piece number: \t ");
int pieceNum = input.nextInt();
System.out.print("Enter row number for piece " + pieceNum + ": \t ");
int rowNum = input.nextInt();
input.nextLine();
System.out.print("Enter a column number for piece " + pieceNum + ": \t ");
int columnNum = input.nextInt();
input.nextLine();
}
System.out.println(listOfNumbers);
listOfNumbers.printTable();
}
}
Chess.java
public class Chess {
private int pieceNum;
private int rowNum;
private int columnNum;
// piece
public int getpieceNum(){
return pieceNum;
}
public void setpieceNum(int piece){
pieceNum = piece;
}
// row
public int getrowNum(){
return rowNum;
}
public void setrowNum(int row){
rowNum = row;
}
// column
public int getcolumnNum(){
return columnNum;
}
public void setcolumnNum(int column){
columnNum = column;
}
public String toString(){
return "Piece " + pieceNum + " Row " + rowNum + " Column " + columnNum;
}
}
ChessList.java
import java.util.ArrayList;
public class ChessList {
private ArrayList<Chess> chessList = new ArrayList<>();
private String listName;
public ChessList(String name) {
this.listName = name;
}
/*
public void addChess(int piece, int row, int column){
Chess newPiece = new Chess(piece, row, column);
chessList.add(newPiece);
}
*/
public String toString(){
String valueString = "\nThe chessboard holds the follwing assets:\n";
for(Chess elem : chessList){
valueString += elem + " \n";
}
return valueString;
}
public void printTable(){
System.out.println("Piece\tRow\tColumn");
**// BELOW CODE DOES NOT DISPLAY USER INPUT DATA AS AN OUTPUT OF EACH PIECE, ROW, COLUMN**
for(Chess elem : chessList){
System.out.println(elem.getname() + "\t" + elem.getrowNum() + "\t" + elem.getcolumnNum() + "\n");
}
}
}

ChessList listOfNumbers = new ChessList("Chessboard");
needs to be changed to
ChessList listOfNumbers = new ChessList();
since ChessList does not have a constructor that takes a String parameter.
OR you could implement a constructor that saves a String:
public class ChessList {
private ArrayList<Chess> chessList = new ArrayList<>();
private String listName; // Type changed to String!
public ChessList(String name) {
this.listName = name;
}
// Your other mothods here ...
}

Your object ChessList doesn't have a constructor. In Java it sets up a default constructor that takes no parameters. Which is what you are trying to use but you are passing it a String.
Should be this:
ChessList listOfNumbers = new ChessList();
If you want to pass a String to the constructor to set a name for the ChessList then you need to create a constructor in your ChessList class that accepts a String.

DemoSalesPerson2.java:15: error: constructor SalesPerson in class SalesPerson cannot be applied to given types;

Whenever I compile my code, I receive the following errors:
constructor SalesPerson in class SalesPerson cannot be applied to
given types; error: constructor Player in class Player cannot be
applied to given types;
But it doesn't list any types. The code in question is
Modify the DemoSalesperson application so each Salesperson has a successive ID number from 111 through 120 and a sales value that ranges from $25,000 to $70,000, increasing by $5,000 for each successive Salesperson. Save the file as DemoSalesperson2.java.*/
SalesPerson class:
public class SalesPerson {
// Data fields for Salesperson include an integer ID number and a double annual sales amount
private int idNumber;
private double salesAmount;
//Methods include a constructor that requires values for both data fields, as well as get and set methods for each of the data fields.
public SalesPerson(int idNum, double salesAmt) {
idNumber = idNum;
salesAmount = salesAmt;
}
public int getIdNumber() {
return idNumber;
}
public void setIdNumber(int idNum) {
idNumber = idNum;
}
public double getSalesAmount() {
return salesAmount;
}
public void setSalesAmount(double salesAmt) {
salesAmount = salesAmt;
}
}
Driver:
public class DemoSalesPerson2 {
public static void main(String[] args) {
SalesPerson s1 = new SalesPerson(111, 0);
final int NUM_PERSON = 10;
SalesPerson[] num = new SalesPerson[NUM_PERSON];
for (int x = 1; x < num.length; x++) {
// NUM_PERSON
num[x] = new SalesPerson((111 + x + "|" + 25000 + 5000 * (x)));
System.out.println(x + " " + s1.getIdNumber() + " " + s1.getSalesAmount());
}
}
}

Change this: num[x] = new SalesPerson((111 + x + "|" + 25000 + 5000 * (x)));
to this: num[x] = new SalesPerson((111 + x), (25000 + 5000 * (x)));
You had it right here SalesPerson s1 = new SalesPerson(111, 0);.
Notice the difference between the two constructor calls.
As Sssss pointed out, you're handing in a String as the constructor param when your method requires two ints.
Code jotted down here, haven't tested it. Should get you pointed in the right direction however.

public class DemoSalesPerson2
{
public static void main(String[] args)
{
SalesPerson[] num = new SalesPerson[10];
final int START_NUM =111;
final double START_SALARY=25_000;
for (int x =0; x<num.length; x++) {
num[x] =new SalesPerson(START_NUM+x,START_SALARY+5000*(x));
System.out.println(num[x].getIdNumber()+" "+num[x].getSalesAmount() );
}
}}
try this!!

Java program grading

I've been working on this program for hours and I can't figure out how to get the program to actually print the grades from the scores Text file
public class Assign7{
private double finalScore;
private double private_quiz1;
private double private_quiz2;
private double private_midTerm;
private double private_final;
private final char grade;
public Assign7(double finalScore){
private_quiz1 = 1.25;
private_quiz2 = 1.25;
private_midTerm = 0.25;
private_final = 0.50;
if (finalScore >= 90) {
grade = 'A';
} else if (finalScore >= 80) {
grade = 'B';
} else if (finalScore >= 70) {
grade = 'C';
} else if (finalScore>= 60) {
grade = 'D';
} else {
grade = 'F';
}
}
public String toString(){
return finalScore+":"+private_quiz1+":"+private_quiz2+":"+private_midTerm+":"+private_final;
}
}
this code compiles as well as this one
import java.util.*;
import java.io.*;
public class Assign7Test{
public static void main(String[] args)throws Exception{
int q1,q2;
int m = 0;
int f = 0;
int Record ;
String name;
Scanner myIn = new Scanner( new File("scores.txt") );
System.out.println( myIn.nextLine() +" avg "+"letter");
while( myIn.hasNext() ){
name = myIn.next();
q1 = myIn.nextInt();
q2 = myIn.nextInt();
m = myIn.nextInt();
f = myIn.nextInt();
Record myR = new Record( name, q1,q2,m,f);
System.out.println(myR);
}
}
public static class Record {
public Record() {
}
public Record(String name, int q1, int q2, int m, int f)
{
}
}
}
once a compile the code i get this which dosent exactly compute the numbers I have in the scores.txt
Name quiz1 quiz2 midterm final avg letter
Assign7Test$Record#4bcc946b
Assign7Test$Record#642423
Exception in thread "main" java.until.InputMismatchException
at java.until.Scanner.throwFor(Unknown Source)
at java.until.Scanner.next(Unknown Source)
at java.until.Scanner.nextInt(Unknown Source)
at java.until.Scanner.nextInt(Unknown Source)
at Assign7Test.main(Assign7Test.java:25)

Exception aside, you actually are printing objects of type Record. What you would need to do is override toString() to provide a decent representation of your object.
#Override
public String toString() {
return "Something meaningful about your Record object.";
}
I also note that you're advancing the Scanner by use of nextLine() in System.out.println('...'). You may want to comment that part out of your code.

The reason you are getting this error is because of the fact that you are expecting an integer, but the next thing your scanner reads is not a number.
Also, put this in your toString of your record to stop printing out addresses.
i.e.
public static class Record {
public Record() {
}
public Record(String name, int q1, int q2, int m, int f)
{
}
public String toString(){}//print out stuff here.
}

change your Record to something like this
public static class Record {
String name;
int q1;
int q2;
int m;
int f;
public Record() {}
public Record(String name, int q1, int q2, int m, int f) {
// here you save the given arguments localy in the Record.
this.name = name;
this.q1 = q1;
this.q2 = q2;
this.m = m;
this.f = f;
}
#Override
public String toString(){
//here you write out the localy saves variables.
//this function is called when you write System.out.println(myRecordInstance);
System.out.println(name + ":" + q1 + ":" + q2 + ":" + m + ":" + f);
}
}
What it does: you have to save the argments by creating the Record.
Additional you have to override the toString method if you want to use System.out.println(myRecordInstance); instead you could write an other function returning a String in your Record and print out the return values of this function like System.out.println(myRecordInstace.writeMe()); Then you ne to add the function to the record.
public String writeMe(){
System.out.println(name + ":" + q1 + ":" + q2 + ":" + m + ":" + f);
}

How to turn static methods into non-static. Small explanation/examples related to java oop

I cant get how to use/create oop code without word static. I read Sun tutorials, have book and examples. I know there are constructors, then "pointer" this etc. I can create some easy non-static methods with return statement. The real problem is, I just don't understand how it works.I hope some communication gives me kick to move on. If someone asks, this is not homework. I just want to learn how to code.
The following code are static methods and some very basic algorithms. I'd like to know how to change it to non-static code with logical steps(please.)
The second code shows some non-static code I can write but not fully understand nor use it as template to rewrite the first code.
Thanks in advance for any hints.
import java.util.Scanner;
/**
*
* #author
*/
public class NumberArray2{
public static int[] table() {
Scanner Scan = new Scanner(System.in);
System.out.println("How many numbers?");
int s = Scan.nextInt();
int[] tab = new int[s];
System.out.println("Write a numbers: ");
for(int i=0; i<tab.length; i++){
tab[i] = Scan.nextInt();
}
System.out.println("");
return tab;
}
static public void output(int [] tab){
for(int i=0; i<tab.length; i++){
if(tab[i] != 0)
System.out.println(tab[i]);
}
}
static public void max(int [] tab){
int maxNum = 0;
for(int i=0; i<tab.length; i++){
if(tab[i] > maxNum)
maxNum = tab[i];
}
//return maxNum;
System.out.println(maxNum);
}
static public void divide(int [] tab){
for(int i=0; i<tab.length; i++){
if((tab[i] % 3 == 0) && tab[i] != 0)
System.out.println(tab[i]);
}
}
static public void average(int [] tab){
int sum = 0;
for(int i=0; i<tab.length; i++)
sum = sum + tab[i];
int avervalue = sum/tab.length;
System.out.println(avervalue);
}
public static void isPrime(int[] tab) {
for (int i = 0; i < tab.length; i++) {
if (isPrimeNum(tab[i])) {
System.out.println(tab[i]);
}
}
}
public static boolean isPrimeNum(int n) {
boolean prime = true;
for (long i = 3; i <= Math.sqrt(n); i += 2) {
if (n % i == 0) {
prime = false;
break;
}
}
if ((n % 2 != 0 && prime && n > 2) || n == 2) {
return true;
} else {
return false;
}
}
public static void main(String[] args) {
int[] inputTable = table();
//int s = table();
System.out.println("Written numbers:");
output(inputTable);
System.out.println("Largest number: ");
max(inputTable);
System.out.println("All numbers that can be divided by three: ");
divide(inputTable);
System.out.println("Average value: ");
average(inputTable);
System.out.println("Prime numbers: ");
isPrime(inputTable);
}
}
Second code
public class Complex {
// datové složky
public double re;
public double im;
// konstruktory
public Complex() {
}
public Complex(double r) {
this(r, 0.0);
}
public Complex(double r, double i) {
re = r;
im = i;
}
public double abs() {
return Math.sqrt(re * re + im * im);
}
public Complex plus(Complex c) {
return new Complex(re + c.re, im + c.im);
}
public Complex minus(Complex c) {
return new Complex(re - c.re, im - c.im);
}
public String toString() {
return "[" + re + ", " + im + "]";
}
}

Let's start with a simple example:
public class Main
{
public static void main(final String[] argv)
{
final Person personA;
final Person personB;
personA = new Person("John", "Doe");
personB = new Person("Jane", "Doe");
System.out.println(personA.getFullName());
System.out.println(personB.getFullName());
}
}
class Person
{
private final String firstName;
private final String lastName;
public Person(final String fName,
final String lName)
{
firstName = fName;
lastName = lName;
}
public String getFullName()
{
return (lastName + ", " + firstName);
}
}
I am going to make a minor change to the getFullName method now:
public String getFullName()
{
return (this.lastName + ", " + this.firstName);
}
Notice the "this." that I now use.
The question is where did "this" come from? It is not declared as a variable anywhere - so it is like magic. It turns out that "this" is a hidden parameter to each instance method (an instance method is a method that is not static). You can essentially think that the compiler takes your code and re-writes it like this (in reality this is not what happens - but I wanted the code to compile):
public class Main
{
public static void main(final String[] argv)
{
final Person personA;
final Person personB;
personA = new Person("John", "Doe");
personB = new Person("Jane", "Doe");
System.out.println(Person.getFullName(personA));
System.out.println(Person.getFullName(personB));
}
}
class Person
{
private final String firstName;
private final String lastName;
public Person(final String fName,
final String lName)
{
firstName = fName;
lastName = lName;
}
public static String getFullName(final Person thisx)
{
return (thisx.lastName + ", " + thisx.firstName);
}
}
So when you are looking at the code remember that instance methods have a hidden parameter that tells it which actual object the variables belong to.
Hopefully this gets you going in the right direction, if so have a stab at re-writing the first class using objects - if you get stuck post what you tried, if you get all the way done post it and I am sure we help you see if you got it right.

First, OOP is based around objects. They should represent (abstract) real-world objects/concepts. The common example being:
Car
properties - engine, gearbox, chasis
methods - ignite, run, brake
The ignite method depends on the engine field.
Static methods are those that do not depend on object state. I.e. they are not associated with the notion of objects. Single-program algorithms, mathematical calculations, and such are preferably static. Why? Because they take an input and produce output, without the need to represent anything in the process, as objects. Furthermore, this saves unnecessary object instantiations.
Take a look at java.lang.Math - it's methods are static for that precise reason.

The program below has been coded by making the methods non-static.
import java.util.Scanner;
public class NumberArray2{
private int tab[]; // Now table becomes an instance variable.
// allocation and initilization of the table now happens in the constructor.
public NumberArray2() {
Scanner Scan = new Scanner(System.in);
System.out.println("How many numbers?");
int s = Scan.nextInt();
tab = new int[s];
System.out.println("Write a numbers: ");
for(int i=0; i<tab.length; i++){
tab[i] = Scan.nextInt();
}
System.out.println("");
}
public void output(){
for(int i=0; i<tab.length; i++){
if(tab[i] != 0)
System.out.println(tab[i]);
}
}
public void max(){
int maxNum = 0;
for(int i=0; i<tab.length; i++){
if(tab[i] > maxNum)
maxNum = tab[i];
}
System.out.println(maxNum);
}
public void divide(){
for(int i=0; i<tab.length; i++){
if((tab[i] % 3 == 0) && tab[i] != 0)
System.out.println(tab[i]);
}
}
public void average(){
int sum = 0;
for(int i=0; i<tab.length; i++)
sum = sum + tab[i];
int avervalue = sum/tab.length;
System.out.println(avervalue);
}
public void isPrime() {
for (int i = 0; i < tab.length; i++) {
if (isPrimeNum(tab[i])) {
System.out.println(tab[i]);
}
}
}
public boolean isPrimeNum(int n) {
boolean prime = true;
for (long i = 3; i <= Math.sqrt(n); i += 2) {
if (n % i == 0) {
prime = false;
break;
}
}
if ((n % 2 != 0 && prime && n > 2) || n == 2) {
return true;
} else {
return false;
}
}
public static void main(String[] args) {
// instatiate the class.
NumberArray2 obj = new NumberArray2();
System.out.println("Written numbers:");
obj.output(); // call the methods on the object..no need to pass table anymore.
System.out.println("Largest number: ");
obj.max();
System.out.println("All numbers that can be divided by three: ");
obj.divide();
System.out.println("Average value: ");
obj.average();
System.out.println("Prime numbers: ");
obj.isPrime();
}
}
Changes made:
int tab[] has now been made an
instance variable.
allocation and initialization of the
table happens in the constructor.
Since this must happen for every
instantiated object, it is better to
keep this in a constructor.
The methods need not be called with
table as an argument as all methods
have full access to the instance
variable(table in this case)
The methods have now been made
non-static, so they cannot be called
using the class name, instead we need
to instantiate the class to create an
object and then call the methods on
that object using the obj.method()
syntax.

It is easy to transform class methods from beeing static to non-static. All you have to do is remove "static" from all method names. (Ofc dont do it in public static void main as you would be unable to run the example)
Example:
public static boolean isPrimeNum(int n) { would become
public boolean isPrimeNum(int n) {
In public static void main where you call the methods you would have to chang your calls from beeing static, to refere to an object of the specified class.
Before:
NumberArray2.isPrimeNum(11);
After:
NumberArray2 numberarray2 = new NumberArray2(); // Create object of given class
numberarray2.isPrimeNum(11); // Call a method of the given object
In NumberArray2 you havent included an constructor (the constructor is like a contractor. He takes the blueprint (class file, NumberArray2) and follows the guidelines to make for example a building (object).
When you deside to not include a constructor the java compilator will add on for you. It would look like this:
public NumberArray2(){};
Hope this helps. And you are right, this looks like homework :D
I belive its common practice to supply the public modifier first. You haven done this in "your" first method, but in the others you have static public. Atleast for readability you should do both (code will compile ether way, as the compilator dosnt care).
The code is clean and easy to read. This is hard to do for someone who is "just want to learn how to code". Hope this helps you on your way with your "justlookslikehomeworkbutisnt" learning.

I'm guessing you're confused of what "static" does. In OOP everything is an object. Every object has its own functions/variables. e.g.
Person john = new Person("John",18);
Person alice = new Person("Alice",17);
if the function to set the 'name' variable would be non static i.e. string setName(string name){} this means that the object john has a name "John" and the object alice has a name "Alice"
static is used when you want to retain a value of something across all objects of the same class.
class Person{
static int amountOfPeopleCreated;
public Person(string name, int age){
amountOfPeopleCreated++;
setName(name);
setAge(age);
}
...
}
so if you'd the value of amountOfPeopleCreated will be the same no matter if you check alice or john.