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Constructor ClassRoll(String f) assignment help, I need to identify why I cannot display the roll

So, basically I have an assignment that requires for me to Write a java program to help maintain a class roll. The program must contain four classes: Student, Exams, ClassRoll and Assignment4(Main).
I have developed all the classes but the ClassRoll constructor it s not performing correctly. When I run the program I am prompted with the file name option, once i enter the file name I see null then the options to modify and / or display the list, but when I enter a command, it does not work, it gives me an error.
The Output should be
Expected input/output:
Assuming that the file data.txt contains:
COP2210
John Doe 50 60 70
Marco Boyle 50 60 73
Eric Munzon 45 100 90
Marry Able 95 100 100
Jack Smith 100 100 100
Elizabeth Gomez 100 100 100
The following is a sample input output run:
What is the name of input file: data.txt
Enter one of the following commands
a or add to add a student in the class roll
sa or average to sort the students based on their average
sn or names to sort the students based on their last names
r or remove to remove a student from the class roll
s or save to save the list of students back to the datafile
Here are my classes;
public class Student {
private String fName = "";
private String lName = "";
private Exam scores;
public Student(String f, String l){
fName=f;
lName=l;
scores = new Exam();
}
public void setScore1(int score) {
scores.setScore1(score);
}
public void setScore2(int score) {
scores.setScore2(score);
}
public void setScore3(int score) {
scores.setScore3(score);
}
public String toString() {
return lName + "\t" + fName + "\t" +
scores.toString();
}
public double getAverage() {
return (scores.getScore1() + scores.getScore2() +
scores.getScore3())/3.0;
}
public boolean equals(String f, String l) {
return f.equals(fName) && l.equals(lName);
}
public int compareTo(Student s){
if (lName.compareTo(s.lName) > 0)
return 1;
else if (lName.compareTo(s.lName) < 0)
return -1;
else if (fName.compareTo(s.fName) > 0)
return 1;
else if (fName.compareTo(s.fName) < 0)
return -1;
else return 0;
}}
public class Exam {
private int score1;
private int score2;
private int score3;
public Exam(){
score1=0;
score2=0;
score3=0;
}
public void setScore1(int score) {
score1=score;
}
public int getScore1() {
return score1;
}
public void setScore2(int score) {
score2=score;
}
public int getScore2() {
return score2;
}
public void setScore3(int score) {
score3=score;
}
public int getScore3() {
return score3;
}
public String toString() {
return Integer.toString(score1) + "\t"
+Integer.toString(score2)
+ "\t" + Integer.toString(score3) + "\t";
}}
public class ClassRoll {
ArrayList students = new ArrayList();
String title;
String fileName;
public ClassRoll(String f) throws IOException {
Scanner fileScan, lineScan;
String line;
fileName = f;
fileScan = new Scanner(new File(f));
title = fileScan.nextLine();
System.out.println("Title =" + title);
while (fileScan.hasNext()) {
line = fileScan.nextLine();
lineScan = new Scanner(line);
lineScan.useDelimiter("\t");
String lastName = lineScan.next();
String firstName = lineScan.next();
Student s = new Student(firstName, lastName);
s.setScore1(lineScan.nextInt());
s.setScore2(lineScan.nextInt());
s.setScore3(lineScan.nextInt());
students.add(s);
//display(students);
ClassRoll c = new ClassRoll();
c.display();
}
}
void display() {
DecimalFormat fmt = new DecimalFormat("0.00");
System.out.println("\t\t\t" + title);
double classAverage = 0.0;
for (int i = 0; i < students.size(); i++) {
Student s = (Student) students.get(i);
System.out.print(s.toString());
System.out.println("\t" + fmt.format(s.getAverage()));
classAverage = classAverage + s.getAverage();
}
System.out.println("\t\t\t" + fmt.format(classAverage /
students.size()));
}
public void insert() {
Scanner input = new Scanner(System.in);
System.out.print("First Name -> ");
String firstName = input.next();
System.out.print("Last Name -> ");
String lastName = input.next();
System.out.print("Score 1 -> ");
int score1 = input.nextInt();
System.out.print("Score 2 -> ");
int score2 = input.nextInt();
System.out.print("Score 3 -> ");
int score3 = input.nextInt();
Student s = new Student(firstName, lastName);
s.setScore1(score1);
s.setScore2(score2);
s.setScore3(score3);
students.add(s);
}
private int search(String f, String l) {
int i = 0;
while (i < students.size()) {
Student s = (Student) students.get(i);
if (s.equals(f, l)) {
return i;
} else {
i++;
}
}
return -1;
}
public Student find() {
Scanner input = new Scanner(System.in);
System.out.print("First Name -> ");
String firstName = input.next();
System.out.print("Last Name -> ");
String lastName = input.next();
int i = search(firstName, lastName);
if (i >= 0) {
return (Student) students.get(i);
} else {
return null;
}}
public void delete() {
Scanner input = new Scanner(System.in);
System.out.print("First Name -> ");
String firstName = input.next();
System.out.print("Last Name -> ");
String lastName = input.next();
int i = search(firstName, lastName);
if (i >= 0) {
students.remove(i);
} else {
System.out.println("Student not found");
}
}
public void sortLastNames() {
for (int i = 0; i < students.size() - 1; i++) {
for (int j = i + 1; j < students.size(); j++) {
Student s1 = (Student) students.get(i);
Student s2 = (Student) students.get(j);
if (s1.compareTo(s2) > 0) {
students.set(i, s2);
students.set(j, s1);
}
}
}}
public void sortAverage() {
for (int i = 0; i < students.size() - 1; i++) {
for (int j = i + 1; j < students.size(); j++) {
Student s1 = (Student) students.get(i);
Student s2 = (Student) students.get(j);
if (s1.getAverage() < s2.getAverage()) {
students.set(i, s2);
students.set(j, s1);
}
}}}
public void save() throws IOException {
PrintWriter out = new PrintWriter(fileName);
out.println(title);
for (int i = 0; i < students.size(); i++) {
Student s = (Student) students.get(i);
out.println(s.toString());
}
out.close();
}}
public class Assignment4bis {
public static void main(String[] args) throws IOException {
Scanner input=new Scanner(System.in);
System.out.print("Enter the name of the input file ->");
String fileName=input.next();
ClassRoll c = new ClassRoll();
c.display();
prompt();
System.out.print("Enter a command --> ");
String ans=input.next();
while (!(ans.equalsIgnoreCase("q") || ans.equalsIgnoreCase("quit")))
{
if(!(ans.equalsIgnoreCase("i") ||ans.equalsIgnoreCase("insert") ||
ans.equalsIgnoreCase("a") || ans.equalsIgnoreCase("average") ||
ans.equalsIgnoreCase("n") || ans.equalsIgnoreCase("names") ||
ans.equalsIgnoreCase("r") || ans.equalsIgnoreCase("remove") ||
ans.equalsIgnoreCase("f") || ans.equalsIgnoreCase("find") ||
ans.equalsIgnoreCase("d") || ans.equalsIgnoreCase("display")))
System.out.println("Bad Command");
else
switch (ans.charAt(0))
{
case 'i': c.insert();
break;
case 'a': c.sortAverage();
c.display();
break;
case 'n': c.sortLastNames();
c.display();
break;
case 'r': c.delete();
c.display();
break;
case 'f': Student s=c.find();
if (s == null)
System.out.println("Student not found");
else System.out.println(s.toString());
break;
case 'd': c.display();
break;
}
prompt();
System.out.print("Enter a command --> ");
ans=input.next();
}
c.save();
System.out.println("Thank you for using this program");
}
public static void prompt(){
System.out.println("Enter one of the following commands");
System.out.println("i or insert to insert a student in the class
roll");
System.out.println("a or average to sort the students based on
their average");
System.out.println("n or names to sort the students based on their
last names");
System.out.println("r or remove to remove a student from the class
roll");
System.out.println("f or find to find a student in the class
roll");
System.out.println("d or display to display the class roll");
System.out.println("q or quit to exit the program");
}}
Errors that I m still getting...
run:
Enter the name of the input file ->data.txt
Title =COP2210
Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Scanner.java:862)
at java.util.Scanner.next(Scanner.java:1371)
at assignment4bis.ClassRoll.<init>(ClassRoll.java:40)
at assignment4bis.Assignment4bis.main(Assignment4bis.java:28)
Java Result: 1

Your ClassRoll "constructor" is a "pseudo-constructor":
public class ClassRoll {
ArrayList students = new ArrayList();
String title;
String fileName;
public void ClassRoll(String f) throws IOException {
Constructors have no return type, so get rid of the void:
public class ClassRoll {
ArrayList students = new ArrayList();
String title;
String fileName;
public ClassRoll(String f) throws IOException {
As a bit of side recommendations:
You look to be mixing user interface with one of your "model" or logical classes, ClassRoll, something you probably shouldn't do. I'd keep all user interface code, including use of a Scanner and File I/O separate from ClassRoll, which likely should just have code to create the collection, to allow other classes to add or remove from the collection, and to allow other classes to query the collection.
Take care to learn and follow Java code formatting rules. You've got some deviations from the standard, including have your class declaration lines indented the same as the method body and variable declaration lines, bunching up of end braces,... This makes your code hard for other Java coders to read and understand.

How to fix my Array class

I am trying to figure out how to get my array to run correctly, I know I have to change the array value to an input but I cannot get the program to compile if any one can help that be great.
I am trying to have the program take input for grades and names of students and in the end output their name and grade.
Edit sorry this is my first it posting i have an error
Student.java:60: error: class, interface, or enum expected I am in java 101 so this is why it is such low level java, we only know the basics
import java.util.Scanner;
public class students
{
public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);
System.out.println("How many students?: ");
int numofstudents = keyboard.nextInt();
Student s = new Student();
s.setMultipleStudents();
s.toString();
System.out.println("Enter the Grade for the student: ");
int gradeofstudnets = keyboard.nextInt();
}
}
and my second class is
import java.util.Scanner;
public class Student
{
Scanner scan = new Scanner(System.in);
private String name;
private int grade;
private int[] multiplegradeinputs = new int[10];
private String[] multipleStudent = new String[10];
public Student()
{
}
public Student(String n, int g)
{
name = n;
grade = g;
}
public String setMultipleStudents()
{
String n = "";
for(int i = 1; i < multipleStudent.length; i++)
{
System.out.println("Enter student #" + i +" name: " );
n = scan.nextLine();
multipleStudent[i] = n;
}
return null;
}
public String multiplegradeinputs()
{
for(int i = 1; i <multiplegradeinputs.length; i++)
{
System.out.println("Enter the Grade of the student#" + i +" : ");
grade = scan.nextInt();
multiplegradeinputs[i] = grade;
}
} <--- error here
public String toString()
{
String temp = "";
for(int i = 1; i < multipleStudent.length; i++)
{
temp += multipleStudent[i] + " ";
}
return temp;
}
}

Add return statement in your multiplegradeinputs() method:
public String multiplegradeinputs()
{
for(int i = 1; i <multiplegradeinputs.length; i++)
{
System.out.println("Enter the Grade of the student#" + i +" : ");
grade = scan.nextInt();
multiplegradeinputs[i] = grade;
}
return null; //Add this line
}
Or change your methods to void return type if they dont return anything.

Class names have to be capitalized in java, so instead of
public class students
you should write
public class Students
Also instead of writing
keyboard.nextInt();
You should write
Integer.parseInt(keyboard.nextLine());
This is mainly because java is full of bugs and technical specifications that you won't find easily. Let me know if this fixes it for you, since you didn't post the exact error message you got.
As for the error that you pointed out, it's because your function expects a String as a return value no matter what, so either change that to void if you can or return a null string. To do that just add the following line at the very end of the method.
return null;

You should create a Student object which holds the properties of the student, e.g. Name and Grades. You should then store all the student objects in some kind of data structure such as an array list in the students class.

Adding to the answer provided by #hitz
You have a bug in the for loops:
for(int i = 1; i <multiplegradeinputs.length; i++)
for(int i = 1; i < multipleStudent.length; i++)
You will never populated multiplegradeinputs[0] and multipleStudent[0] because you start the loop at index == 1 and thus you will have only 9 student names stored instead of 10.
Change to:
for(int i = 0; i <multiplegradeinputs.length; i++)
for(int i = 0; i < multipleStudent.length; i++)
Remember even though the length in 10, the indices always start with 0 in Java and in your case will end with 9.

import java.util.Scanner;
public class Student
{
Scanner scan = new Scanner(System.in);
private String name;
private int grade;
private int[] multiplegradeinputs = new int[10];
private String[] multipleStudent = new String[10];
public Student()
{
}
public Student(String n, int g)
{
name = n;
grade = g;
}
public String setMultipleStudents()
{
String n = "";
for(int i = 1; i < multipleStudent.length; i++)
{
System.out.println("Enter student #" + i +" name: " );
n = scan.nextLine();
multipleStudent[i] = n;
}
return null;
}
public void multiplegradeinputs()
{
for(int i = 1; i <multiplegradeinputs.length; i++)
{
System.out.println("Enter the Grade of the student#" + i +" : ");
grade = scan.nextInt();
multiplegradeinputs[i] = grade;
}
}
public String toString()
{
String temp = "";
for(int i = 1; i < multipleStudent.length; i++)
{
temp += multipleStudent[i] + " ";
}
return temp;
}
}
this is the 2nd class
import java.util.Scanner;
public class students
{
public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);
System.out.println("How many students?: ");
int numofstudents = keyboard.nextInt();
Student s = new Student();
s.setMultipleStudents();
s.toString();
System.out.println("Enter the Grade for the student: ");
int gradeofstudnets = keyboard.nextInt();
}
}

You are missing a return value in the multiplegradeinputs() method.

Array out of bounds exception with scanning user input into an array

Hey I have code for a project im trying to finish up and I keep getting array out of bounds exceptions at a certain part and would like to know how to fix it. My project is to create a reservation system using 3 classes Room,Reservation and a client class. I'm having trouble with my bookRoom class after asking for the number of guests for the room.Any help would be greatly appreciated. The exception occurs at line 57 in the reservation class. The line in question is in bold.
`
public class Reservation {
public void roomInitialization(Room[] room,int numberOfRooms,int numberOfSmokingRooms)
{
boolean smoking=true;
String[] guestName={null,null,null,null};
for (int i=0;i<numberOfRooms;i++)
{
if (i>=numberOfSmokingRooms)
smoking=false;
room[i]=new Room(smoking,false,guestName,null,i+1);
}
}
public void displayRoomsInfo(Room[] room,int numberOfRooms)
{
for (int i=0;i<numberOfRooms;i++)
{
System.out.println("Room " + room[i].getroomNumber() + "\t" +
(room[i].getsmoking()?"Smoking room":"Non-Smoking Room"));
if (room[i].getoccupied())
{
System.out.print("Phone: "+room[i].getguestPhone()+"\t");
for(int j=0;j<4;j++)
System.out.print(room[i].getguestName()[j]+"\t");
System.out.println();
}
}
}
public void bookRoom (Room[] room, int numberOfRooms)
{
displayRoomsInfo(room, numberOfRooms);
Scanner scan = new Scanner(System.in);
Scanner scans = new Scanner(System.in);
Scanner scand = new Scanner(System.in);
System.out.print("Enter a Room Number: ");
int roomNumber = scan.nextInt()-1;
if (roomNumber >=0 && roomNumber < 30){
room[roomNumber].setoccupied(true);
System.out.print("Enter a Phone Number: ");
String guestPhone = scans.nextLine();
room[roomNumber].setguestPhone(guestPhone);
System.out.print("Enter number of guests:(Max of 4 per room) ");
int guests = scand.nextInt()-1;
String[] guestName = new String[guests];
for (int i=0;i<guestName.length;i++)
System.out.print("Enter guest names: ");
**guestName[guests] = scand.next();**
room[roomNumber].setguestName(guestName);
}
else
System.out.println("Enter a valid room number");
}
public void checkOut(Room[] room)
{
Scanner scan=new Scanner(System.in);
int roomNumber;
String[] nullguestName={null,null,null,null};
do
{
System.out.print("Enter the room number: ");
roomNumber=scan.nextInt()-1;
if (roomNumber>=0 && roomNumber<30)
break;
else
System.out.println("Enter a valid room number");
}while(true);
if (room[roomNumber].getoccupied())
{
room[roomNumber].setoccupied(false);
room[roomNumber].setguestPhone(null);
room[roomNumber].setguestName(nullguestName);
}
else
System.out.println("room "+(roomNumber+1)+" is already empty");
}
}
`
Code for the other classes
package hotel;
public class Room {
private boolean smoking;
private boolean occupied;
private String[] guestName=new String[4];
private String guestPhone;
private int roomNumber;
public Room (boolean smoking,boolean occupied,String[] guestName, String guestPhone,int roomNumber)
{
this.smoking=smoking;
this.occupied=occupied;
for (int i=0;i<4;i++)
this.guestName[i]=guestName[i];
this.guestPhone=guestPhone;
this.roomNumber=roomNumber;
}
public void setoccupied(boolean occupied) {
this.occupied = occupied;
}
public void setsmoking(boolean smoking) {
this.smoking = smoking;
}
public void setroomNumber(int roomNumber) {
this.roomNumber = roomNumber;
}
public void setguestPhone(String guestPhone) {
this.guestPhone = guestPhone;
}
public void setguestName(String[] guestName)
{
for (int i=0;i<4;i++)
this.guestName[i]=guestName[i];
}
public boolean getsmoking() {
return this.smoking;
}
public boolean getoccupied(){
return this.occupied;
}
public String getguestPhone(){
return this.guestPhone;
}
public int getroomNumber() {
return this.roomNumber;
}
public String[] getguestName()
{
String[] tempguestName=new String[4];
for (int i=0;i<4;i++)
tempguestName[i]=this.guestName[i];
return tempguestName;
}
}
package hotel;
import java.util.Scanner;
public class ReservationDemo {
public static void main(String[]args)
{
final int numberOfRooms=30, numberOfSmokingRooms=5;
Room[] room=new Room[numberOfRooms];
Reservation reservation=new Reservation();
reservation.roomInitialization(room,numberOfRooms,numberOfSmokingRooms);
int userSelection;
Scanner scan=new Scanner(System.in);
do
{
System.out.println("Press: 1-Book room\t2-checkout\t3-display all rooms\t4-exit. ");
userSelection=scan.nextInt();
switch(userSelection)
{
case 1:
reservation.bookRoom(room,numberOfRooms);
break;
case 2:
reservation.checkOut(room);
break;
case 3:
reservation.displayRoomsInfo(room,numberOfRooms);
break;
case 4:
System.exit(0);
default:
break;
}
}while (true);
}
}

There are lots of mistake in your code.
First-- Use the following code instead of your version in Reservation class
System.out.print("Enter number of guests:(Max of 4 per room) ");
int guests = scand.nextInt();
String[] guestName = new String[guests];
for (int i=0;i<guestName.length;i++) {
System.out.print("Enter guest names: ");
guestName[i] = scand.next();
}
Second -- Use the following method in Room class instead of the existing one.
public void setguestName(String[] guestName)
{
for (int i=0;i<guestName.length;i++)
this.guestName[i]=guestName[i];
}
Let me know what you achieve

You are trying to index into the guests array using the variable guests which is the size of the array, you should be using the iteration counter variable i instead:
guestName[guests] = scand.next() should be guestName[i] = scand.next()

Method to display records.

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.

Running a loop again and passing the control to Main class in Java after output

I am trying to make a simple JAVA program that will help a user select a car of his choice.
public class CarSelector {
static CarSelector start = new CarSelector();
public String BodyType(String a){
String hatchBack, SUV, MUV, compactSedan, sedan, saloon, miniVan, convertible, hybrid, coupe;
if(a.equalsIgnoreCase("a")){
hatchBack = "polo";
System.out.println("We recommend: " +hatchBack);
}
String b = "";
if(a.equalsIgnoreCase("b")){
SUV = "Fortuner";
System.out.println("We recommend: " +SUV);
}
if(a.equalsIgnoreCase("c")){
compactSedan = "Amaze";
System.out.println("We recommend: " +compactSedan);
}
if(a.equalsIgnoreCase("d")){
sedan = "Vento";
System.out.println("We recommend: " +sedan);
}
if(a.equalsIgnoreCase("e")){
saloon = "Corolla";
System.out.println("We recommend: " +saloon);
}
if(a.equalsIgnoreCase("f")){
MUV = "Innova";
System.out.println("We recommend: " +MUV);
}
else{
System.out.println("Incorrect choice.");
System.out.println(a);
//start.BodyType(a);
return null;
}
System.out.println("We recommend: " +a);
return null ;
}
public int PriceRange(){
int price5 = 5;
int price10 = 10;
int price15 = 15;
int price20 = 20;
int price25 = 25;
int price30 = 30;
return 0 ;
}
public String SegmentBest(){
//string type of the best cars within price range
return null;
}
public int OnRoadPrice(){
//return int of on road price
return 0;
}
public String Manufacturer(){
//all manufacturers with their models available
String Toyota, Volkswagen, Honda;
String i1= "Toyota";
String i2= "Volkswagen";
String i3= "Honda";
return null;
}
public int SeatingCapacity(){
//return integer seating capacity
return 0;
}
public String ReviewLink(){
return null;
}
public String LatestReleases(){
return null;
}
public String FuelType(){
return null;
}
public static void main (String[] args){
Scanner input = new Scanner(System.in);
String option;
System.out.println("Welcome to car selector: ");
System.out.println("Choose according to: ");
System.out.println("A:Body Type");
System.out.println("B: Manufacturer");
System.out.println("C: Price Range");
option = input.nextLine();
if( option.equalsIgnoreCase("a")){
System.out.println("A: Hatchback");
System.out.println("B: SUV");
System.out.println("C: MUV");
System.out.println("D: Sedan");
System.out.println("E: Saloon");
System.out.println("F: Compact Sedan");
String optionA = input.nextLine();
start.BodyType(optionA);
}
}
}
The code is simple. A walkthrough: The main class will prompt the user to make a choice of how he wants to choose a car. Given option "A" as a choice will run the first method. Here are my queries
Within the BodyType method, I would like to run the set of IF statements again if the user enters anything other than a,b,c,d,e,f
How can I hand the control back to the main class (run a specific code from MAIN method) and also start a method from another method (from BodyType to PriceRange). I hope I was clear. Thanks, Cheers!

you can play it now...
import java.util.Scanner;
public class CarSelector {
static CarSelector start = new CarSelector();
static String[] bodytypes = new String[]{"hatchBack", "SUV", "MUV", "compactSedan", "sedan",
"saloon", "miniVan", "convertible", "hybrid", "coupe"};
static String[] manufacturers = new String[]{"Toyota", "Volkswagen", "Honda"};
private String getBodyType(int bt) {
if(bt >= bodytypes.length){
System.err.println("Incorrect choice.");
return null;
}else{
System.out.println("We recommend: " + bodytypes[bt]);
return bodytypes[bt];
}
}
public static String getManufacturer(int mf) {
if(mf >= manufacturers.length){
System.err.println("Incorrect choice.");
return null;
}else{
System.out.println("We recommend: " + manufacturers[mf]);
return manufacturers[mf];
}
}
public static void main(String[] args) {
String bodyType = "";
String manufacturer = "";
Scanner input = new Scanner(System.in);
String option;
System.out.println("Welcome to car selector: ");
System.out.println("Choose according to: ");
pringSelectType();
option = input.nextLine();
while(!option.equalsIgnoreCase("o")){
if (option.equalsIgnoreCase("a")) {
for(int a = 0; a < bodytypes.length ; a++){
System.out.println(a+": "+ bodytypes[a]);
}
option = input.nextLine();
bodyType = start.getBodyType(Integer.parseInt(option));
pringSelectType();
option = input.nextLine();
}else if (option.equalsIgnoreCase("b")) {
for(int a = 0; a < manufacturers.length ; a++){
System.out.println(a+": "+ manufacturers[a]);
}
option = input.nextLine();
manufacturer = getManufacturer(Integer.parseInt(option));
pringSelectType();
option = input.nextLine();
}else{
option = input.nextLine();
System.err.println(("input a right choice"));
pringSelectType();
option = input.nextLine();
}
}
System.out.println("");
System.out.println("it's your choice below: ");
System.out.println("bodyType : "+ bodyType);
System.out.println("manufacturer : "+ manufacturer);
}
private static void pringSelectType() {
System.out.println("A:Body Type");
System.out.println("B: Manufacturer");
System.out.println("C: Price Range");
}
}
i delete some unused method,and change some code.
i don't make any note,cause i think it's easy enough..
if u have some problem,comment it,i will see.
PS:when u want to over the select system,input o.it will be done.