Method to display records.

Method to display records. - java

Hey guys just need help on how to finish this up.
Code Snippet:
import java.util.Scanner;
public class CreateLoans implements LoanConstants {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
//set the program here
float prime;
float amountOfLoan = 0;
String customerFirstName;
String customerLastName;
String LoanType;
System.out.println("Please Enter the current prime interest rate");
prime = sc.nextInt() / 100f;
//ask for Personal or Business
System.out.println("are you after a business or personal loan? Type business or personal");
LoanType = sc.next();
//enter the Loan amount
System.out.println("Enter the amount of loan");
amountOfLoan = sc.nextInt();
//enter Customer Names
System.out.println("Enter First Name");
customerFirstName = sc.next();
System.out.println("Enter Last Name");
customerLastName = sc.next();
//enter the term
System.out.println("Enter the Type of Loan you want. 1 = short tem , 2 = medium term , 3 = long term");
int t = sc.nextInt();
}
}
I need to display the records I have asked and store the object into an array.
so this where I'm stuck. I need to do this in a loop 5 times and by the end display all records in an array, if that makes sense?

Try this way :
import java.util.Scanner;
public class CreateLoans {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
Loan[] loans = new Loan[5];
for(int i=0;i<5;i++) {
loans[i] = new Loan();
System.out.println("Please Enter the current prime interest rate");
float prime = sc.nextInt();
prime = (float)(prime/100f);
loans[i].setPrime(prime);
//ask for Personal or Business
System.out.println("are you after a business or personal loan? Type business or personal");
String loanType = sc.next();
loans[i].setLoanType(loanType);
//enter the Loan amount
System.out.println("Enter the amount of loan");
float amountOfLoan = sc.nextFloat();
loans[i].setAmountOfLoan(amountOfLoan);
//enter Customer Names
System.out.println("Enter First Name");
String customerFirstName = sc.next();
loans[i].setCustomerFirstName(customerFirstName);
System.out.println("Enter Last Name");
String customerLastName = sc.next();
loans[i].setCustomerLastName(customerLastName);
}
//Display details
for(int i=0;i<5;i++) {
System.out.println(loans[i]);
}
}
}
class Loan {
private float prime;
private float amountOfLoan = 0;
private String customerFirstName;
private String customerLastName;
private String LoanType;
public float getPrime() {
return prime;
}
public void setPrime(float prime) {
this.prime = prime;
}
public float getAmountOfLoan() {
return amountOfLoan;
}
public void setAmountOfLoan(float amountOfLoan) {
this.amountOfLoan = amountOfLoan;
}
public String getCustomerFirstName() {
return customerFirstName;
}
public void setCustomerFirstName(String customerFirstName) {
this.customerFirstName = customerFirstName;
}
public String getCustomerLastName() {
return customerLastName;
}
public void setCustomerLastName(String customerLastName) {
this.customerLastName = customerLastName;
}
public String getLoanType() {
return LoanType;
}
public void setLoanType(String loanType) {
LoanType = loanType;
}
#Override
public String toString() {
return "First Name : " + customerFirstName + "\n" +
"Last Name : " + customerLastName + "\n" +
"Amount of Loan : " + amountOfLoan + "\n" +
"Loan type : " + LoanType + "\n" +
"Prime : " + prime + "\n\n";
}
}
Create a Loan class and put all necessary details as private members into it and override toString() method.

Make a ArrayList and add all the variables inside that list
ArrayList arrlist = new ArrayList();
arrlist.add(prime);
arrlist.add(LoanType);
arrlist.add(amountOfLoan);
arrlist.add(customerFirstName );
arrlist.add(customerLastName);
arrlist.add(t);
and display the ArrayList
System.out.println(arrlist);

Example of a loop
int[] nums = new int[5];
String[] names = new String[5];
Scanner input = new Scanner(System.in);
for (int i = 0; i < 5; i++){
System.out.println("Enter a number: ");
int number = input.nextInt();
// insert into array
nums[i] = number;
System.out.println("Enter a name: ");
String name = input.nextLne();
// insert into array
names[i] = name;
}
Everything you want to be looped 5 times, you can put inside the loop. Whatever values you want to store, you can do that in the loop also.

Related

Condition is not verifying the validity of the input

I'm doing an assignment that asks a user to input a student name, and then quiz scores until the user chooses to stop. It then calculates the total score and the average of all those scores and outputs them to the screen.
We are moving on to the subject of inheritance and now we are requested to make a class called MonitoredStudent which extends Student. The point of the MonitoredStudent class is to check if the average is above a user inputted average and display whether the student is off academic probation.
I have got most of the program written and when I input just one score (such as 71, when the average I set is 70) it is still displaying that I am on academic probation, even though the one quiz score is above the average I set of 70.
The main issue is that no matter what integer is set for the minimum passing average, I always get a return of false.
I added the "return false" statement in the isOffProbation method as when I add an if-else statement to check if the averageScore (from the Student class) is less than or equal to minPassingAvg eclipse tells me that the method needs a return type of boolean.
public class MonitoredStudent extends Student {
int minPassingAvg;
public MonitoredStudent(){
super();
minPassingAvg = 0;
}
public MonitoredStudent(String name, int minPassingAvg) {
super(name);
this.minPassingAvg = minPassingAvg;
}
public int getMinPassingAvg() {
return minPassingAvg;
}
public void setMinPassingAvg(int minPassingAvg) {
this.minPassingAvg = minPassingAvg;
}
boolean isOffProbation() {
if(getAverageScore() >= minPassingAvg)
return true;
return false;
}
}
This is the Student super class:
public class Student{
private String name;
private double totalScore;
private int quizCount;
public Student(){
name = "";
totalScore = 0;
quizCount = 0;
}
public Student(String n){
name = n;
totalScore = 0;
quizCount = 0;
}
public void setName(String aName){
name = aName;
}
public String getName(){
return name;
}
public void addQuiz(int score){
if(score >= 0 && score <= 100){
totalScore = totalScore + score;
quizCount = quizCount + 1;
}else{
System.out.println("Score must be between 0 and 100, inclusive");
}
}
public double getTotalScore(){
return totalScore;
}
public double getAverageScore(){
return totalScore / quizCount;
}
}
This is the main method:
import java.util.Scanner;
public class MonitoredStudentTester{
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
MonitoredStudent monStu = new MonitoredStudent();
String repeat = "n";
int currentScore = 0;
int minPassAv;
System.out.println("Enter the student's name:");
String stuName = scan.next();
Student sName = new Student(stuName);
System.out.println("What is the minimum passing average score: ");
minPassAv = scan.nextInt();
Student stu = new Student();
do {
System.out.println("Enter a quiz score: ");
currentScore = scan.nextInt();
stu.addQuiz(currentScore);
monStu.setMinPassingAvg(currentScore);
System.out.println("Would you like to enter any more scores?: (Y for yes, N for no)");
scan.nextLine();
repeat = scan.nextLine();
}while(repeat.equalsIgnoreCase("y"));
String studName = stu.getName();
double totalScore = stu.getTotalScore();
double avgScore = stu.getAverageScore();
boolean offProb = monStu.isOffProbation();
System.out.println(studName + "'s Total Score is: " + totalScore);
System.out.println(studName + "'s Average Score is: " + avgScore);
System.out.println("Is " + studName + "off academic probation?: " + offProb);
}
}

You main class should be something like this.
public class MonitoredStudentTester {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
MonitoredStudent monStu = new MonitoredStudent();
String repeat = "n";
int currentScore = 0;
int minPassAv;
System.out.println("Enter the student's name:");
monStu.setName(scan.next());
System.out.println("What is the minimum passing average score: ");
minPassAv = scan.nextInt();
do {
System.out.println("Enter a quiz score: ");
currentScore = scan.nextInt();
monStu.addQuiz(currentScore);
monStu.setMinPassingAvg(minPassAv);
System.out.println("Would you like to enter any more scores?: (Y for yes, N for no)");
scan.nextLine();
repeat = scan.nextLine();
} while (repeat.equalsIgnoreCase("y"));
String studName = monStu.getName();
double totalScore = monStu.getTotalScore();
double avgScore = monStu.getAverageScore();
boolean offProb = monStu.isOffProbation();
System.out.println(studName + "'s Total Score is: " + totalScore);
System.out.println(studName + "'s Average Score is: " + avgScore);
System.out.println("Is " + studName + "off academic probation?: " + offProb);
}
}
When using inheritance you just need to create an object of child class.

How do I update the element inside the arraylist?

public class billing{
private int id;
//File f=new File("C:/Users/Bingus/Documents/Projects/accounts.txt");
private String bc;
private String bd;
private String customerName;
private String customerAddress;
private String customerNumber;
private String periodT;
private String periodF;
private double presentR;
private double previousR;
private double previousB;
private double dueTotal;
private static ArrayList<Account> accountList = new ArrayList<>();
public billing(int id,String bc,String bd,String customerName,String customerAddress,String customerNumber,String periodT,String periodF,double presentR,double previousR,double previousB,double dueTotal){
this.id = id;
this.bc = bc;
this.bd = bd;
this.customerName = customerName;
this.customerAddress = customerAddress;
this.customerNumber = customerNumber;
this.periodT = periodT;
this.periodF = periodF;
this.presentR = presentR;
this.previousR = previousR;
this.previousB = previousB;
this.dueTotal = dueTotal;
}
public int getId(){
return id;
}
public String getBc(){
return bc;
}
public String getBd(){
return bd;
}
public String getCustomerName(){
return customerName;
}
public String getCustomerAddress(){
return customerAddress;
}
public String getCustomerNumber(){
return customerNumber;
}
public String getPeriodT(){
return periodT;
}
public String getPeriodF(){
return periodF;
}
public double getPresentR(){
return presentR;
}
public double getPreviousR(){
return previousR;
}
public double getPreviousB(){
return previousB;
}
public double getDue(){
return dueTotal;
}
public static void main(String[] args){
Scanner scanner = new Scanner (System.in);
Scanner kb = new Scanner (System.in);
int user_choice;
int x = 0;
do{
System.out.println();
System.out.println("1) New Billing");
System.out.println("2) Add Existing Billing");
System.out.println("3) View Billing Account ID");
System.out.println("4) View By Date");
System.out.println("5) Update Existing Billing");
System.out.println("6) Delete Billing Account");
System.out.println("7) Display All Account");
System.out.println("8) Exit");
System.out.println();
System.out.print("Enter choice [1-8]: ");
user_choice = scanner.nextInt();
switch (user_choice){
case 1:
int min = 1000;
int max = 9999;
int randomStr = (int)(Math.random() * (max - min + 1) + min);
int id = randomStr;
System.out.println("Your Account Number is : " + id);
System.out.print("Enter Billing Code: ");
String bc = scanner.next();
System.out.print("Enter Billing Date(dd/mm/yyyy): ");
String bd = scanner.next();
System.out.print("Enter Customer Name: ");
String customerName = kb.nextLine();
System.out.print("Enter Customer Address: ");
String customerAddress = kb.nextLine();
System.out.print("Enter Customer Number: ");
String customerNumber = scanner.next();
System.out.print("Enter Period To: ");
String periodT = scanner.next();
System.out.print("Enter Period From: ");
String periodF = scanner.next();
System.out.print("Enter Present Reading: ");
double presentR = scanner.nextDouble();
System.out.print("Enter Previous Reading: ");
double previousR = scanner.nextDouble();
System.out.print("Enter Previous Balance: ");
double previousB = scanner.nextDouble();
double dueTotal = getTotalDue(presentR,previousR,previousB);
Account user = new Account(id,bc,bd,customerName,customerAddress,customerNumber,periodT,periodF,presentR,previousR,previousB,dueTotal);
accountList.add(user);
break;
case 2:
case 3:
System.out.print("Enter Account Number: ");
int a = scanner.nextInt();
for(int i = 0; i<accountList.size();i++){
if(a == accountList.get(i).getId()){
System.out.println("Account ID: " + accountList.get(i).getId());
System.out.println("Customer Name: " +accountList.get(i).getCustomerName());
System.out.println("Customer Address: " + accountList.get(i).getCustomerAddress());
System.out.print("Customer Number: " + accountList.get(i).getCustomerNumber());
}
}
System.out.println("\nBilling Code\t\tBilling Date\t\tAmount Due");
for(int i = 0; i<accountList.size();i++){
if(a == accountList.get(i).getId())
{
System.out.println(accountList.get(i).getBc()+"\t\t\t"+accountList.get(i).getBd()+"\t\t\t"+accountList.get(i).getDue());
}
}
break;
case 4:
case 5:
System.out.print("Enter Account Number: ");
a = scanner.nextInt();
for(int i = 0; i<accountList.size();i++){
if(a == accountList.get(i).getId())
{
System.out.println("Your Account Number is : " + accountList.get(i).getId());
System.out.print("Enter Billing Code: ");
String bCode = scanner.next();
String c = accountList.get(i).getBc(); //this is the part in which i am having a hard time to fix, ive used the set but still i cannot change the element inside.
int index = accountList.indexOf(c);
accountList.set(index, bCode);
}
}
break;
case 6:
System.out.print("Enter Account Number: ");
a = scanner.nextInt();
System.out.print("Enter Billing Code: ");
String b = scanner.next();
for(int i = 0; i<accountList.size();i++){
if(a == accountList.get(i).getId()){
if(b.equals(accountList.get(i).getBc())){
accountList.remove(i);
System.out.print("\nAccount Removed\n");
}else{
System.out.print("Invalid Billing Code\n");
}
}else if(a != accountList.get(i).getId()){
System.out.print("Invalid Account Number or Number not in the database.\n");
}else{
System.out.print("Try Again\n");
}
}
break;
case 7:
System.out.println("Account ID\t\tBilling Code\t\tAccount Name\t\tTotal Due\t\tPresent R\t\tPrevious R");
Collections.sort(accountList,Collections.reverseOrder());
for(int i=0; i<accountList.size();i++){
System.out.println(accountList.get(i).getId() + "\t\t\t"+accountList.get(i).getBc()+ "\t\t\t"+accountList.get(i).getCustomerName()+ "\t\t\t"+accountList.get(i).getDue()+"\t\t\t"+accountList.get(i).getPresentR()+ "\t\t\t"+accountList.get(i).getPreviousR());
}
break;
}
}while(user_choice!=8);
}
I'm new to programming in Java and I'm still learning towards it. I'm making my billing system which calcualtes the payment. My problem for this is how can I change or update the value which is already in the arraylist, I've tried the set() but I cannot make it work. using arraylist is a big jump for me and I haven't yet got a hang of it. I've watched youtube vids but they seem to show non user input arry lists
Any help?
[1]: https://i.stack.imgur.com/HhF33.png

There are two ways to do it.
First Option is Loop the list and reach the object you want to change, update its attributes. Since the object is accessed by reference, whatever values you will change it will effect.
Second option is remove the object at that index, create a new object and insert at that position.
public void testArrayList ()
{
class MyData
{
String Id = "";
String Name = "";
public MyData () {}
public MyData (String id, String name) {
Id= id;
Name = name;
}
public String toString ()
{
return " Id=" + Id + " Name=" + Name;
}
}
ArrayList myDList = new ArrayList ();
myDList.add(new MyData("1", "John"));
myDList.add(new MyData("2", "Mike"));
myDList.add(new MyData("3", "Tom"));
System.err.println ("Org List " + myDList);
MyData tmp = (MyData) myDList.get(1);
tmp.Id = "22";
tmp.Name = tmp.Name + " Changed";
System.err.println ("Mod List (Observe second Object ) " + myDList);
}

You need to set the value in ArrayList to be an object of type Account.
1.You need to get an object of type Account and use settter method to update bcode
2. Set that Account object back to ArrayList

Code TL:DR. Do you have a set method in your Account class?
//set method example
public void setBc(String newBc){ //can also use other data types as parameters
this.bc = newBc;
}
If so you can just
accountList.get(i).setBc("This New BCODE"); //The parameter can also be a variable of string type

Your code:
System.out.println("Your Account Number is : " + accountList.get(i).getId());
System.out.print("Enter Billing Code: ");
String bCode = scanner.next();
String c = accountList.get(i).getBc(); //this is the part in which i am having a hard time to fix, ive used the set but still i cannot change the element inside.
int index = accountList.indexOf(c);
accountList.set(index, bCode);
If you want to update billing code in an account then get the account object and update the user entered bCode on the object. Also, you don't have to put the account back in the list:
System.out.println("Your Account Number is : " + accountList.get(i).getId());
System.out.print("Enter Billing Code: ");
String bCode = scanner.next();
Account existing = accountList.get(i);
//create new account with same data except bCode
Account updated = new Account(existing.getId(),bCode, existing.getBd(),/*do same for rest of the fields */);
int index = accountList.indexOf(existing);
accountList.set(index, updated);

You have to change this part in Your program
…
Billing billing = accountList.get(i);
//String c = billing.getBc(); // this is the part in which I am having a hard time to fix, I've used
// the set but still I cannot change the element inside.
billing.setBc( yourNewBc );
//int index = accountList.indexOf(c);
//accountList.set(index, billing);
…
class names are capitalized in Java

Here in this example we have iterated over the list and modified the values of the object.
Please make a setter to the values you want to modify and follow something like this.
public class Arr {
public static void main(String args[]){
ArrayList<Person> array = new ArrayList();
Scanner sc=new Scanner(System.in);
while (true){
System.out.println("1.add 2. modify 3.view list ; anything else to to quit");
int choice = sc.nextInt();
if (choice==1){
System.out.println("Enter ID then salary");
int id = sc.nextInt();
int salary = sc.nextInt();
Person p = new Person(id,salary);
array.add(p);
System.out.println("Done");
}
else if (choice==2){
System.out.println("Enter ID");
int id = sc.nextInt();
for (int i = 0; i < array.size(); i++){
Person p = array.get(i);
if (p.getId()==id){
System.out.println("value exits. Enter salary to be modified:");
int salary = sc.nextInt();
p.setSalary(salary);
}
}
System.out.println("Done");
}
else if (choice==3){
for (int i = 0; i < array.size(); i++)
System.out.print(" " + array.get(i).getId() + " " + array.get(i).getSalary());
}
else
break;
}
}
}
public class Person {
int id;
int salary;
public Person(int id, int salary) {
this.id = id;
this.salary = salary;
}
public int getId() {
return id;
}
public int getSalary() {
return salary;
}
public void setSalary(int salary) {
this.salary = salary;
}
}

Java passing class array into array

I am a student and looking for help with an assignment. Here is the task: Create a CollegeCourse class. The class contains fields for the course ID (for example, “CIS 210”), credit hours (for example, 3), and a letter grade (for example, ‘A’).
Include get() and set()methods for each field. Create a Student class containing an ID number and an array of five CollegeCourse objects. Create a get() and set() method for the Student ID number. Also create a get() method that returns one of the Student’s CollegeCourses; the method takes an integer argument and returns the CollegeCourse in that position (0 through 4). Next, create a set() method that sets the value of one of the Student’s CollegeCourses; the method takes two arguments—a CollegeCourse and an integer representing the CollegeCourse’s position (0 through 4).
I am getting runtime errors on the second for loop where I am trying to get the data into the course array. It is asking for both the CourseID and Hours in the same line and regardless of what I respond with it I am getting an error, it almost seems like it is trying to get all the arrays variables at the same time. Here is my code which includes three classes. Any help to send me in the right direction is appreciated as I have spent a ton of time already researching to resolve.
public class CollegeCourse {
private String courseId;
private int creditHours;
private char grade;
public CollegeCourse(String id, int hours, char grade)
{
courseId=id;
creditHours = hours;
this.grade = grade;
}
public void setCourseId(String id)
{
courseId = id;//Assign course id to local variable
}
public String getCourseId()
{
return courseId;//Provide access to course id
}
public void setHours(int hours)
{
creditHours = hours;//Assign course id to local variable
}
public int getHours()
{
return creditHours;//Provide access to course id
}
public void setGrade(char grade)
{
this.grade = grade;//Assign course id to local variable
}
public char getGrade()
{
return grade;//Provide access to course id
}
}
Student Class
public class Student {
final int NUM_COURSES = 5;
private int studentId;
private CollegeCourse courseAdd;//Declares a course object
private CollegeCourse[] courses = new CollegeCourse[NUM_COURSES];
//constructor using user input
public Student(int studentId)
{
this.studentId=studentId;
}
public void setStudentId(int id)
{
studentId = id;//Assign course id to local variable
}
public int getStudentId()
{
return studentId;//Provide access to course id
}
public void setCourse(int index, CollegeCourse course)
{
courses[index] = course;
}
public CollegeCourse getCourse(int index)
{
return courses[index];
//do I need code to return the courseId hours, grade
}
}
InputGrades Class
import java.util.Scanner;
public class InputGrades {
public static void main(String[] args) {
final int NUM_STUDENTS = 2;
final int NUM_COURSES = 3;
Student[] students = new Student[NUM_STUDENTS];
int s;//subscript to display the students
int c;//subscript to display courses
int stId;
int csIndex;
String courseId = "";
int hours = 0;
//String gradeInput;
char grade = 'z';
CollegeCourse course = new CollegeCourse(courseId,hours, grade);//not sure if I am handling this correctly
Scanner input = new Scanner(System.in);
for(s = 0; s<NUM_STUDENTS; ++s)
{
students[s] = new Student(s);
System.out.print("Enter ID for student #" + (s+1) + ":");
stId = input.nextInt();
input.nextLine();
students[s].setStudentId(stId);
for(c=0; c < NUM_COURSES; ++c)
{
csIndex=c;
System.out.print("Enter course ID #" + (c+1) + ":");
courseId = input.nextLine();
course.setCourseId(courseId);
System.out.print("Enter hours:");
hours = input.nextInt();
input.nextLine();
course.setHours(hours);
String enteredGrade = "";
while(enteredGrade.length()!=1) {
System.out.print("Enter grade:");
enteredGrade = input.nextLine();
if(enteredGrade.length()==1) {
grade = enteredGrade.charAt(0);
} else {
System.out.println("Type only one character!");
}
}
course.setGrade(grade);
students[s].setCourse(csIndex, course);
}
}
for(s = 0; s<NUM_STUDENTS; ++s)
{
System.out.print("\nStudent# " +
students[s].getStudentId());
System.out.println();
for(c=0;c<NUM_COURSES;++c)
System.out.print(students[s].getCourse(c) + " ");
System.out.println();
}
}
}

After input.nextInt() you need to add one more input.nextLine(); and than you can read grade.
System.out.print("Enter hours:");
hours = input.nextInt();
input.nextLine();
course.setHours(hours);
Why it is needed? See this question: Scanner is skipping nextLine() after using next(), nextInt() or other nextFoo() methods
You should add a very simple length validation when you input the grade:
String enteredGrade = "";
while(enteredGrade.length()!=1) {
System.out.print("Enter grade:");
enteredGrade = input.nextLine();
if(enteredGrade.length()==1) {
grade = enteredGrade.charAt(0);
} else {
System.out.println("Type only one character!");
}
}
so the full main class code:
import java.util.Scanner;
/**
* Created by dkis on 2016.10.22..
*/
public class App {
public static void main(String[] args) {
final int NUM_STUDENTS = 10;
final int NUM_COURSES = 5;
Student[] students = new Student[NUM_STUDENTS];
//String name;
int s;//subscript to display the students
int c;//subscript to display courses
int stId;
int csIndex;
String courseId = "";
int hours = 0;
char grade = 'z';
CollegeCourse course = new CollegeCourse(courseId,hours, grade);//not sure if I am handling this correctly
Scanner input = new Scanner(System.in);
for(s = 0; s<NUM_STUDENTS; ++s)
{
students[s] = new Student(s);
System.out.print("Enter ID for student #" + s+1 + ":");
stId = input.nextInt();
input.nextLine();
students[s].setStudentId(stId);
for(c=0; c < NUM_COURSES; ++c)
{
//CollegeCourse course = students[s].getCourse(c);
csIndex=c;
System.out.print("Enter course ID#" + c+1 + ":");
courseId = input.nextLine();
course.setCourseId(courseId);
System.out.print("Enter hours:");
hours = input.nextInt();
input.nextLine();
course.setHours(hours);
String enteredGrade = "";
while(enteredGrade.length()!=1) {
System.out.print("Enter grade:");
enteredGrade = input.nextLine();
if(enteredGrade.length()==1) {
grade = enteredGrade.charAt(0);
} else {
System.out.println("Type only one character!");
}
}
course.setGrade(grade);
students[s].setCourse(csIndex, course);
}
}
for(s = 0; s<NUM_STUDENTS; ++s)
{
System.out.print("\nStudent# " +
students[s].getStudentId());
for(c=0;c<NUM_COURSES;++c)
System.out.print(students[s].getCourse(c) + " ");
System.out.println();
}
}
}

Calling methods of an object that is already stored in an ArrayList

Everything works so far in my program but I'm having trouble with this section of my code:
else if(input.equals("2")) {
System.out.println("Enter the stock symbol:");
symbol2 = in.next();
System.out.println("Enter the number of shares you wish to sell:");
sellshares = in.nextInt();
String tempsymbol = "";
for(int i=0; i<array1.size(); i++) {
tempsymbol = (array1.get(i)).getSymbol();
if(symbol2.equals(tempsymbol)) {
System.out.println("The dollar cost averaged price per share (LIFO): " + (array1.get(i)).averageCost(sellshares));
System.out.println("The dollar cost averaged price per share (FIFO): " + (array2.get(i)).averageCost(sellshares));
}
}
}
It'll go through the loop but tempsymbol will always = "". Why doesn't array1 return anything?
Here's all my code. Apologies ahead of time if any parts are redundant or messy.
import java.util.*;
public class Whoop {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String input = "";
String symbol = "";
String name = "";
int shares = 0;
double price = 0;
String symbol2 = "";
int sellshares = 0;
int rolling = 0;
stack theStack = null;
queue theQ = null;
String loopcheck = "1";
ArrayList<stack> array1 = new ArrayList<stack>();
ArrayList<queue> array2 = new ArrayList<queue>();
while(loopcheck.equals("1")) {
System.out.println("Press 1 to enter a new stock or press 2 to find the LIFO and FIFO dollar cost average for the number of shares sold");
input = in.next();
if(input.equals("1")) {
System.out.println("Enter the stock symbol:");
symbol = in.nextLine();
in.nextLine();
System.out.println("Enter the stock name:");
name = in.nextLine();
System.out.println("Enter the number of shares bought:");
shares = in.nextInt();
System.out.println("Enter the price per share when purchased");
price = in.nextDouble();
theStack = new stack(symbol,name,shares,price);
theQ = new queue(symbol,name,shares,price);
System.out.println("Press 1 to continue entering new shares or press 2 to finish input for " + theStack.getName());
rolling = in.nextInt();
while(rolling == 1) {
System.out.println("Enter the number of shares bought:");
shares = in.nextInt();
System.out.println("Enter the price per share when purchased");
price = in.nextDouble();
theStack.bigPush(shares, price);
theQ.bigAdd(shares, price);
System.out.println("Press 1 to continue entering new shares or press 2 to finish input for " + theStack.getName());
rolling = in.nextInt();
}
array1.add(theStack); //I added the objects after all the values were finalized
array2.add(theQ);
}
else if(input.equals("2")) {
System.out.println("Enter the stock symbol:");
symbol2 = in.next();
System.out.println("Enter the number of shares you wish to sell:");
sellshares = in.nextInt();
String tempsymbol = "";
for(int i=0; i<array1.size(); i++) {
tempsymbol = (array1.get(i)).getSymbol();
if(symbol2.equals(tempsymbol)) {
System.out.println("The dollar cost averaged price per share (LIFO): " + (array1.get(i)).averageCost(sellshares));
System.out.println("The dollar cost averaged price per share (FIFO): " + (array2.get(i)).averageCost(sellshares));
}
}
}
else {
System.out.println("Input invalid ):");
System.exit(0);
}
System.out.println("Press 1 to continue working with your stocks or press anything else to finish up");
loopcheck = in.next();
}
System.out.println("END");
}
}
This is my queue class which works perfectly fine.
import java.util.LinkedList;
public class queue<E> {
private LinkedList<Double> linklist;
private String symbol;
private String name;
private int shares;
private Double price;
public queue(String symbol2, String name2, int shares2, Double price2) {
linklist = new LinkedList<Double>();
shares = shares2;
price = price2;
symbol = symbol2;
name = name2;
bigAdd(shares, price);
}
public String getName() {
return name;
}
public String getSymbol() {
return symbol;
}
public void add(Double e) {
linklist.add(e);
}
public Double take() {
return linklist.poll();
}
public void bigAdd (int shares2, Double price2) {
while(shares2>0) {
linklist.add(price2);
shares2--;
}
}
public double averageCost(int shares2) {
double average = 0;
int sizer = 0;
while(sizer < shares2) {
average = average + linklist.poll();
sizer++;
}
average = average/shares2;
return average;
}
And this is my stack class which also works fine.
import java.util.*;
public class stack {
private ArrayList<Double> stackArray = new ArrayList<Double>();
private int top;
private String symbol;
private String name;
private int shares;
private Double price;
public stack(String symbol2, String name2, int shares2, Double price2) {
symbol = symbol2;
name = name2;
shares=shares2;
price=price2;
top = -1;
bigPush(shares, price);
}
public double averageCost(int shares2) {
double average = 0;
int sizer = shares2;
while(sizer > 0) {
average = average + stackArray.get(top--);
sizer--;
}
average = average/shares2;
return average;
}
public void push(Double value) {
stackArray.add(++top, value);
}
public Double pop() {
return stackArray.get(top--);
}
public String getName() {
return name;
}
public String getSymbol() {
return symbol;
}
public void bigPush(int shares2, Double price2) {
while(shares2>0) {
stackArray.add(++top, price2);
shares2--;
}
}
public static void main(String[] args) {
stack theStack = new stack("Dave", "Franco", 2,10.0);
theStack.bigPush(2,20.0);
System.out.println(theStack.getSymbol());
}
}
Also heres an example of my output:
Press 1 to enter a new stock or press 2 to find the LIFO and FIFO dollar cost average for the number of shares sold
1
Enter the stock symbol:
DAVE
Enter the stock name:
FRANCO
Enter the number of shares bought:
5
Enter the price per share when purchased
5
Press 1 to continue entering new shares or press 2 to finish input for FRANCO
2
Press 1 to continue working with your stocks or press anything else to finish up
1
Press 1 to enter a new stock or press 2 to find the LIFO and FIFO dollar cost average for the number of shares sold
2
Enter the stock symbol:
DAVE
Enter the number of shares you wish to sell:
1
//AND THEN NOTHING HERE WHEN IT SHOULD RETURN AVERAGECOST()
Press 1 to continue working with your stocks or press anything else to finish up

Following your long code,
tt looks like it all boils down to a wrong usage of the Scanner class :
while(loopcheck.equals("1")) {
System.out.println("Press 1 to enter a new stock or press 2 to find the LIFO and FIFO dollar cost average for the number of shares sold");
input = in.next();
if(input.equals("1")) {
System.out.println("Enter the stock symbol:");
symbol = in.nextLine(); // problem here
in.nextLine();
this assigns an empty String to symbol, because it consumes the end of line of the previous in.next().
If you change it to :
while(loopcheck.equals("1")) {
System.out.println("Press 1 to enter a new stock or press 2 to find the LIFO and FIFO dollar cost average for the number of shares sold");
input = in.next();
in.nextLine();
if(input.equals("1")) {
System.out.println("Enter the stock symbol:");
symbol = in.nextLine();
it will work.
Edit :
It looks like you are aware of the need to sometimes call in.nextLine() without using its returned value, but you put in.nextLine() in the wrong place.

Input 2 names and output the average age

This is for personal knowledge of how this works, is not for school
Program requirements - Enter 2 Names. Have the program find the assigned values with the names and print the average between the two people.
I an not sure how to get the Scanner to take the input and go to the class to make it start processing. For example, in the main method if I sysout print a, it should display the string inside the method getName.
import java.util.Scanner;
public class RainFallApp {
public static void main(String[] args) {
rainfall a = new rainfall();
rainfall b = new rainfall();
System.out.println(a);
// System.out.print("Please enter month one: ");
// Scanner = new Scanner(System.in);
// rain1 = aRain;
// System.out.print("Please enter month two: ");
// Scanner = new Scanner(System.in);
//
// int average = (rain1 + rain2) / 2;
// System.out.println("The average rainfall for " + var +
"and " + var2 +"is: " + average);
}
}
class rainfall {
String rainamt;
String Rain_Amount;
Scanner input = new Scanner(System.in);
String rainMonth = input.nextLine();
String rainAmount(String rainMonth) {
Rain_Amount = getName(rainMonth);
return Rain_Amount;
}
private String getName(String rainMonth) {
if (rainMonth.equals("Jan")) {
rainamt = "3.3";
}
else if (rainMonth.equals("Feb")) {
rainamt = "2.2";
}
else {
System.out.println("Not a valid month name");
}
return rainamt;
}
}

You only need to say Scanner scanner = new Scanner(System.in); once. Then you can use the scanner's nextLine() method to input data. It returns a string, so be sure to store the result in a variable.

I completed my program
import java.util.Scanner;
public class RainFallApp {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Please enter the first month: ");
String aMonth = input.nextLine();
System.out.print("Please enter the second month: ");
String bMonth = input.nextLine();
rainfall aRainfall = new rainfall();
String aName = aRainfall.rainAmount(aMonth);
Double aAmount = Double.parseDouble(aName);
rainfall bRainfall = new rainfall();
String bName = bRainfall.rainAmount(bMonth);
Double bAmount = Double.parseDouble(bName);
double Avg = (aAmount + bAmount) / 2;
System.out.println("\nIn the month of " + aMonth + " it had "
+ aAmount + " inches of rain.");
System.out.println("In the month of " + bMonth + " it had "
+ bAmount + " inches of rain.");
System.out.println("The average rainfall between the two months is: " + Avg);
}
}
class rainfall {
private String Rain_Amount;
String rainAmount(String rainMonth) {
Rain_Amount = getAmount(rainMonth);
return Rain_Amount;
}
private String getAmount(String rainMonth) {
if (rainMonth.equals("Jan")) {
Rain_Amount = "3.3";
}
else if (rainMonth.equals("Feb")) {
Rain_Amount = "2.3";
}
else {
System.out.println("Not a valid month name");
}
return Rain_Amount;
}
}

Develop Reference

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

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