I am trying to make an erase function to delete the teams of the tournament using the team code (value c in the constructor). Firstly I want to check if that team exists in the objects I made in the main method. Is that possible to do that using an if statement?
Exercise:
Create a java application that stores data for various football teams. Each team has a name, a code and the current points in the championship. In your class create methods for registering new teams, erasing existing teams using their code and showing a list for all the teams currently active in the championship
package assignment.exercise4;
public class Data {
private String name = "";
private int code = 0;
private static int register;
private int erase;
private int currentpoints = 0;
public Data(int c, int points, String n) { //constructor
code = c;
this.currentpoints = points;
name = n;
}
public void Erase(int c)
{
code = c;
if(code != 0)
System.out.println("Team with Code: "+code+" has been erased" );
else
System.out.print("Team with code "+code+" does not exist!");
}
public void Register(String newTeam,int code)
{
name = newTeam;
this.code = code;
System.out.println("New Team " + name + " registered with code " + code);
}
public void print()
{
System.out.println("Team name: " + name + "\nTeam code: " + code + "\nTeam points: " + currentpoints + "\n");
}
}
/*
public static void main(String[] args) {
System.out.println("\nList of Teams: \n");
Data t1 = new Data(110,42,"Juventus");
Data t2= new Data(105,45,"Manchester City");
Data t3= new Data(240,50,"Barcelona");
Data t4= new Data(122,36,"Arsenal");
Data Team = new Data(0,0,""); //use for erase
t1.print();
t2.print();
t3.print();
t4.print();
System.out.println("Teams erased: \n");
Team.Erase(110);
Team.Erase(122);
Team.Erase(0);
System.out.println("\n\nTeams Registered: \n");
t1.Register("Real madrid", 11);
t1.Register("Atletico Madric", 112);
}
}
*/
What are you trying to erase the teams from?
If they were in a list, for example...
Data t1 = new Data(110,42,"Juventus");
Data t2= new Data(105,45,"Manchester City");
Data t3= new Data(240,50,"Barcelona");
Data t4= new Data(122,36,"Arsenal");
List<Data> teams = Arrays.asList(t1, t2, t3, t4);
...you could create a list with a team erased like this...
public List<Data> erase(List<Data> team, int id) {
return team.stream()
.filter(t -> t.getId() != id)
.collect(Collectors.toList());
}
So...
List<Data> remainingTeam = erase(team, 122); // Removes Arsenal
...would remove the first element from the list
I will not answer this to elaborately since it is homework. I will try to give you a hint though.
If you have a team and want to do something with it. Otherwise you just have a team which just stays there in a particular scope (if you do not know what scope is, look it up!). If you have a team you most likely want do do something with it. In this case you seem to want to store information about the teams to use in a championship. Important to note here is that the teams are not the focus here. The real focus is the Championship. The teams are just a part of the championship. There can still be a championship even if all teams does not choose to participate. But you want all teams choosing to participate to be registered to this particular championship (eg UEFA Champions League).
This leads to something called aggregate or association depending on how hard you want to tie the object to the championship. However you do probably not need to pursue these terms any further at this point. What is important to remember is that there is an "has a" relation between the championship and the teams. The championship "has a" collection of participating teams. This is normally reflected in this way in code,
public class Championship {
private Team[] teams; // Or List<Team>, Collection<Team>, HashMap<Team>, ...
}
The Championship can then have methods for registering a team, removing a team, updating status, etc...
public void register(Team t) {
if (numberOfTeams < teams.length) {
teams[numberOfTeams] = t; // Index starts at zero
numberOfTeams++;
} else {
throw new IndexOutOfBoundsException("The list is full. " +
"No more teams may be registered!")
}
}
Even though the function erasing a team was requested, I believe I will not write it down. This design is so different from your original intent, so that writing the erase function will likely solve your complete homework. However, you do actually not have to erase the team it is perfectly possible to just overwrite the position with the next team as,
teams[i] = teams[i+1];
Hope this helps!
Short answer:
public void erase(int id) {
// who needs an if statement, if we can use predicates?
teams.removeIf(team -> team.getId() == id);
}
But this will not work with your current code. Your current code misses the container for your teams.
Longer answer:
For the fun of it. Solving your homework:
class Team {
int id;
String name;
int points;
Team(int id, String name, int points) {
this.id = id;
this.name = name;
this.points = points;
}
#Override
public String toString() {
// ugly formatted... another homework? ;-)
return "Team '" + name + "' (" + id + "): " + points;
}
}
Note, that I will not add any getter or setter, nor will I care about visibility here. I will leave that as another homework for you.
class Championship {
List<Team> teams = new ArrayList<>();
void register(Team team) {
teams.add(team);
}
void erase(int id) {
teams.removeIf(team -> team.id == id);
}
#Override
public String toString() {
// for additional fun... sorted by descending points
return "=== Championship table ===\n"
+ teams.stream()
.sorted((o1, o2) -> Integer.compare(o2.points, o1.points))
.map(Objects::toString)
.collect(Collectors.joining("\n"));
}
}
Somewhere else:
public static void main(String[] args) {
Championship championship = new Championship();
championship.register(new Team(1, "not the best ones", 3));
championship.register(new Team(2, "The better ones", 7));
championship.register(new Team(3, "The winners", 11));
System.out.println(championship);
championship.erase(3);
System.out.println(championship);
}
Output:
=== Championship table ===
Team 'The winners' (3): 11
Team 'The better ones' (2): 7
Team 'not the best ones' (1): 3
=== Championship table ===
Team 'The better ones' (2): 7
Team 'not the best ones' (1): 3
Too much of information? Just start with something like a championship-class or at least use a collection of Teams (e.g. List<Team>).
By the way... Do not deliver this solution as your homework, except you understand what is going on and you can explain it with your own words. Otherwise you are only betraying yourself.
Related
What I have below is producing the desired results by print some employee details along with weekly / monthly wages as appropriate.
However I understand that I should not be inputting data in the constructor as I've done.
I need to prompt for a hours worked value only for "PartTimeEmployees", just not the way I've done it.
I've tested with For-Each loops, Enhanced For loops and using the instanceOf operator.
If I could get some guidance/hints or examples of how to accomplish what is currently being done in the constructor, but in the TestEmployee class instead that would be great.
Mostly I'm not sure how to even describe what I'm trying to achieve. This hinders Googling somewhat. (Help with a better title would also be great)
Thanks in advance.
public class TestEmployee
{
public static void main(String[] args)
{
int size;
Employee[] employees = new Employee[4];
employees[0] = new FullTimeEmployee("Jane", 26000);
employees[1] = new PartTimeEmployee("Jack");
employees[2] = new FullTimeEmployee("Lucy", 52000);
employees[3] = new PartTimeEmployee("Lenny");
for(int i = 0; i < employees.length; i++)
{
employees[i].print();
}
}
}
Class: PartTimeEmployee - Constructor:
public PartTimeEmployee(String thisName)
{
super(thisName);
System.out.println("Please enter the number of hours worked by " + thisName + ": ");
numHours = keyboard.nextInt();
setHours(numHours);
}
If I get your question, below might fit with your need -
First of all create generic Employee class -
class Employee {
private String name;
private int workingHours;
private final boolean IS_PART_TIME_EMP;
public Employee(String name, int workingHours) {
this.name = name;
this.workingHours = workingHours;
this.IS_PART_TIME_EMP = false;
}
public Employee(String name) {
this.name = name;
this.IS_PART_TIME_EMP = true;
}
public String getName() {
return name;
}
public int getWorkingHours() {
return workingHours;
}
public void setWorkingHours(int workingHours) {
this.workingHours = workingHours;
}
public boolean isPartTimeEmployee() {
return IS_PART_TIME_EMP;
}
}
Now you can use it as per your requirement.
Employee[] employees = new Employee[4];
employees[0] = new Employee("Jane", 26000);
employees[1] = new Employee("Jack");
employees[2] = new Employee("Lucy", 52000);
employees[3] = new Employee("Lenny");
Scanner sc = new Scanner(System.in);
for (Employee employee : employees) {
if(employee.isPartTimeEmployee()) {
System.out.println("Please enter working hours by " + employee.getName() + ": ");
int numHours = sc.nextInt();
employee.setWorkingHours(numHours);
}
}
Constructor is not meant for user input.Its main intention is to initialize object of that class.
Instead of doing that in constructor,you can try something like this
employees[1] = new PartTimeEmployee("Jack");
System.out.println("Please enter the number of hours worked by " + employees[1].getName()+ ": ");
numHours = keyboard.nextInt();
employees[1].setHours(numHours);
You most likely will have some logical main loop in your program, like
while(!quit) {
// 1. ask if you want to add part time or full time employee
// 2. ask proper questions
// 3. call correct constructor
}
Writing such small pseudo code algorithm should be self explanatory and get you going.
Step one: presentation of options available for user and reading user input.
Step two: performing actions depending on user input from step 1
Step three: final call to proper constructor depending on results from steps 1 and 2
If I understood your question correctly (which I'm really not sure of) you want to prompt for the employee data in the main method.
In that case I'd use a loop and query the following things:
name of the employee
does the employee work full time? (y/n)
if yes: what is the wage? (assume hours = whatever a full time employee works a day)
if no: how many hours? (and probably the hourly wage as well)
Then use that information to construct an Employee object (I don't see any need for the subclasses here).
I am having issues with objects and classes.
I had to define two classes:
Course: a course has a code, an name and a number of credits
Teacher: a teacher has a first name and last name. He can be asked his full name.
So far so good, I got no issue with them, but I have to do next assignment which I was trying to do in the last 2 days and I could not find a proper answer:
Extend the code of the class teacher. A teacher also has a list of courses he can teach. Add an array of Courses to the code. Also add a function addCourse(Course aCourse) to the code. Courses can also be removed from teachers.
I could do everyting in my way but no clue on how to create the addCourse(Course aCourse) method.
Find below my coding, but it must be according to the method described:
public class Course {
private String courseCode;
private String courseName;
private String numberOfCredits;
public Course(String courseCode, String courseName, String numberOfCredits) {
super();
this.courseCode = courseCode;
this.courseName = courseName;
this.numberOfCredits = numberOfCredits;
}
public void print() {
System.out.println(courseCode + "\t" + courseName + "\t" + numberOfCredits);
}
public static void main(String[] args) {
Course[] courseArray = new Course[4];
System.out.println("Code" + "\t" + "Name" + "\t" + "Credits");
courseArray[0] = new Course("001", "Hist", "3");
courseArray[1] = new Course("002", "Phy", "3");
courseArray[2] = new Course("003", "Math", "3");
courseArray[3] = new Course("004", "Log", "3");
for (int i = 0; i < courseArray.length; i++) {
courseArray[i].print();
}
}
}
Arrays are fixed length collections of objects, so you'll need to decide how big your array should be. Let's call the length of your array MAX_COURSES. A more advanced solution might resize the array when required, but I get the impression this is beyond the scope of your course.
So you need to define the Course[] array as a field of your Teacher class. The syntax of array declarations is quite easy to research, so I won't put that in here. Just make sure your array length is equal to MAX_COURSES.
Now, to add courses to the array, you need to know where to put them. To keep track of the next free position of the array, the easiest thing to do is to declare a field in your class:
private int numCourses = 0;
Now, when you add a new course, insert the course into the index specified by numCourses. Make sure you increment numCourses after you've added the course.
Finally, you ought to test to see if your array is full before you agree to insert a new course into the array, i.e. check if numCourses is smaller than MAX_COURSES. If it's not, you need to throw an exception.
I would recommend using a collection (such as a List) rather than an array. The code would look something like:
public class Teacher {
private final String firstName;
private final String lastName;
private final List<Course> courses = new ArrayList<Course>();
public Teacher(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
public void addCourse(Course course) {
courses.add(course);
}
}
Based on that example, you should be able to add the removeCourse method yourself, and any other method you need to operate on the list of courses.
If you want to return the list as an array, you could always convert it, e.g:
public Course[] getCourses() {
return courses.toArray(new Course[courses.size()]);
}
If you really need to use an array for the data structure based on your assignment, something you can try when adding and removing courses, is to construct a list from the array of courses, add or remove a course from that list, the convert the list back to an array of courses.
There's really 3 options here.
Option 1
If you're allowed to use List constructs:
private List<Course> courses = new ArrayList<Course>();
public void addCourse(Course aCourse)
{
if (aCourse == null)
{
return;
}
courses.add(aCourse);
}
Option 2
The uses arrays, but it doesn't scale. Assume that a teacher can only have a maximum of X courses, in my example 10:
// Yes, I stole Duncan's variable names
private final int MAX_COURSES = 10;
private int numCourses = 0;
private Course[] courses = new Course[MAX_COURSES];
public void addCourse(Course aCourse) {
if (aCourse == null)
{
return;
}
if (numCourses >= courses.length)
{
return;
}
courses[numCourses] = aCourse;
numCourses++;
}
Option 3
This is identical to the previous item, but is a bit smarter in that it can resize the array... by creating a new one using the static method Arrays.copyOf
// Yes, I stole Duncan's variable names
private final int MAX_COURSES = 10;
private int numCourses = 0;
private Course[] courses = new Course[MAX_COURSES];
public void addCourse(Course aCourse) {
if (aCourse == null)
{
return;
}
if (numCourses >= courses.length)
{
int size = courses.length * 2;
courses = Arrays.copyOf(courses, size);
}
courses[numCourses] = aCourse;
numCourses++;
}
So I'm writing a program for an assignment where I store Patients into a TreeSet. The problemn I'm having is I have to implement a method to discharge a specefic patient from the TreeSet.
for(int i = 0; i < 10 ; i++){
Random ag = new Random();
int age = ag.nextInt(99) + 1;
Names randomname = Names.getRandom();
String name = randomname.name();
String sex;
if(Math.random() > 0.5)sex = "female";
else sex = "male";
Random sn = new Random();
int serial = sn.nextInt(10000) + 1;
Address randomAddress = Address.getRandom();
String address = randomAddress.name();
Hospital.admitPatient(new Patient(age, name, sex, serial, Birthday.produceBirthday(), address));
}
So Thats how I am looping to get the Patients info and stats for the Patient Object. The admit patient method adds them to the TreeSet.
public static void admitPatient(Patient obj){
if(numofPatients < maxPatients){
patientList1.add(obj);
}
}
The Problem I'm having is withbthe Discharge patient method. Where I don't know what to put in the method
public static void dischargePatient(What do i put here in the driver when i call this method?){
patientList1.remove(w/e i put up there);
}
Since I didn't name the Objects of patients when creating them but just inserted them straight into the TreeSet I'm not sure exactly how to call them when i call the discharge patient method.
As you usually want to work with selected objects (patients) and not the whole list, you need a way to identify them somehow (for example by name or ID).
Since add and remove are similar, your dischargePatient method will be similar as well. Try
public static void dischargePatient(Patient patient) {
patientList1.remove(patient);
}
To retrieve a patient with a certain ID, you may iterate through your set and return it:
public Patient getPatientByID(String id) {
for (Patient patient : patientList1) {
if (patient.getID().equals(id)) {
return patient;
}
}
}
To remove a patient with ID "1234abc", you could do the following:
dischargePatient(getPatientByID("1234abc"));
Using this pattern, you rebuild the functionality of the map datastructure. Thus it might be better to use a Map (e.g. HashMap<>). Code will be reduced to operations like:
Map<String, Patient> patients = new HashMap<>();
patients.put("1234abc", patient1);
patients.remove("1234abc");
Full code for your example:
public static void admitPatient(Patient patient) {
if(numofPatients < maxPatients){
patients.put(patient.getID(), patient);
}
}
public static void dischargePatient(String id) {
patients.remove(id);
}
Sorry if this is answered somewhere due to me missing something obvious, but I've been googling this for days now and it just doesn't seem to make any sense. I've got 3 years of experience in Javascript and am getting into Java now, so I'm not behind on the basic concepts of anything and such.
I'm using IntelliJ for this, but it fails to point out the problem. The communication (access rights and instantiations) between my classes is fine, the code syntax and variable types are as well, etc, so I really can't tell what it is.
I have a Data class, which just holds "read-only" data for the other classes to use.
public class Data {
// snip
public static int[][] specs = {
{6,1,6,40},
{5,2,5,30},
{5,3,4,40},
{4,4,3,60}
};
}
There's another class that has to read this data when it's initialized.
public class Soldier {
// snip
public int range;
public Soldier() {
int x = ...; // user input
range = Data.specs[x][1];
}
}
The specs array itself contains its data as defined (ie the array is not empty), x is valid as an index of the specs array (ie 0 <= x <= 3), its type is int and Test has read access to the specs array (all confirmed with debug output statements). And yet, when it tries to set the value of range (then and only then, at that exact point), I get the "Index out of bounds" error.
Can someone please tell me what's going wrong when trying to read the array? Or am I right in saying that this is really weird and I need to post the entire code?
Note: a small new test also shows that, if I change the code to first output a manually chosen value from the array and then set the value of range, the console prints the error statement (and exits the program) and follows it up by printing the manually picked value, but assigning the value and then asking to output range only throws the error... That makes absolutely no sense at all!
Edit: I've edited the code above. The class called Test is called Soldier in my code (I'm making a text-based game...). Below's the stack trace, if it's any good without the full code (which is way long). The basic structure of my program is this:
1) Boot contains the main method and instantiates a new Game
2) Game instantiates x Teams
3) each Team instantiates an Army
4) each Army instantiates x Soldiers
Each instance of the classes is set as an attribute of the instantiating class (public Army army; and an Army instantiation in the Team constructor, for example). It's essentially a cascade of constructors instantiating subsequent classes and assigning them as their attributes.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at Army.<init>(Army.java:13)
at Team.<init>(Team.java:19)
at Game.<init>(Game.java:22)
at Boot.main(Boot.java:15)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)5
Edit edit: here's the semi-full code (I'm leaving out the stuff that has absolutely nothing to do with it, including the imports). It's in no particular order and the classes are in separate .java files within the IntelliJ project. The game continues up to the point where a new Soldier asks for its type to be designated (the function performing the user input is working fine and validating the input as proven by a technically identical other part of the game).
public class Boot {
public static void main(String[] args) {
Object[] games = new Object[] {};
if (Lib.userConfirmPrompt("Start the game?") == true) {
do {
games[games.length] = new Game();
}
while (Lib.userConfirmPrompt("Do you want to play again?") == true);
}
System.exit(0);
}
}
public class Game {
public Object[] teams = new Object[] {};
public Game() {
for (int i = 0;i < settings.xbots + 1;i++) {
teams[teams.length] = new Team(this);
}
}
}
public class Team {
public Game game;
public Army army;
public Team(Game p) {
game = p;
army = new Army(this);
}
}
public class Army {
public Team team;
public static Object[] soldiers = new Object[] {};
public Army(Team p) {
team = p;
for (int i = 0;i < team.game.settings.xsoldiers;i++) {
soldiers[soldiers.length] = new Soldier(this);
}
}
}
public class Soldier {
private Army army;
public int sight;
public int range;
public int distance;
public int damage;
public Soldier(Army p) {
army = p;
int type = Lib.userTxtIntOptionsPrompt(Data.isoldiertypes);
// HERE is where it crashes, type is assigned and valid but the array access fails
sight = Data.isoldierspecs[type][0];
range = Data.isoldierspecs[type][1];
distance = Data.isoldierspecs[type][2];
damage = Data.isoldierspecs[type][3];
}
}
public class Data {
public static List isoldiertypes = Arrays.asList("Scout","Private","Machinegunner","Grenadier");
public static int[][] isoldierspecs = {
{6,1,6,40},
{5,2,5,30},
{5,3,4,40},
{4,4,3,60}
};
}
public class Lib {
private static Scanner input = new Scanner(System.in);
// output
// default: 1 query string to print
public static void outBase(String query) {
System.out.print(query);
}
public static void outStd(String query) {
outBase(query + "\n");
}
// end of output
// input
// default: 1 query string to print,
// query and input are in-line (exception: userConfirmPrompt prints query block-wise and default instruction in-line before input),
// keeps user hostage until valid input is given (exception: userPrompt returns blindly)
public static String userPrompt(String query) {
outBase(query);
return input.nextLine();
}
public static String userTxtPrompt(String query) {
String menuinput = null;
do {
if (menuinput != null) {
userHostage();
}
menuinput = userPrompt(query);
} while (menuinput.length() == 0);
return menuinput;
}
public static int userIntPrompt(String query) {
String menuinput = null;
do {
if (menuinput != null) {
userHostage();
}
menuinput = userTxtPrompt(query);
} while(menuinput.matches("^-?\\d+$") == false);
return new Integer(menuinput);
}
// end of input
// options input
// default: takes a List of options as argument,
// prints an enumerated list of these options string-wise,
// prompts for a numeral selection of the desired option and returns the number if valid
public static int userTxtIntOptionsPrompt(List options) {
int choice = 0;
Boolean chosen = false;
do {
if (chosen == true) {
userHostage();
} else {
chosen = true;
}
chosen = true;
for (int i = 0;i < options.size() - 2;i++) {
outStd((i + 1) + ") " + options.get(i) + ",");
}
outStd((options.size() - 1) + ") " + options.get(options.size() - 2) + "\nand " + options.size() + ") " + options.get(options.size() - 1) + ".");
choice = userIntPrompt("Enter the number of the option you'd like to select: ") - 1;
} while(choice < 0 || choice >= options.size());
return choice;
}
// end of options input
// miscellaneous
public static void userHostage() {
outStd("Invalid operation. Please try again.");
}
}
The problem is in your Army class:
public static Object[] soldiers = new Object[] {};
You initialize an empty (length == 0) array named soldiers, but later you access:
soldiers[soldiers.length] = new Soldier(this);
This causes the failure.
By definition, soldiers.length is out of the bound of the array (since the bound is from 0 to soldiers.length-1)
To overcome it - make sure you allocate enough space in the array soldiers or use a dynamic array (ArrayList) instead. You can append elements to an ArrayList using ArrayList.add(), and you don't need to know the expected size before filling it up.
The x should be greater than -1 and less than 4.
The stacktrace does not mention the Solder class, its in the conctructor of the Army class.
Any how, only knowing that the index should be within a range is not enough. As a programmer its your duty to validate the index before trying to access an element at that index.
if(index > 0 && index < array.length) {
//then only acess the element at index
Problem is the array soldiers is of size 0.
This line int x = ...; // user input implies that you are taking input in some fashion from the user and accessing the array with it. Are you checking this value to see that is in range (i.e., between 0 and 3)? If not, this may be why your testing works.
Edit: something like this might solve it for you:
public class Army {
public Team team;
public Vector<Soldier> soldiers;
public Army(Team p) {
soldiers = new Vector<Soldier>()
team = p;
for (int i = 0;i < team.game.settings.xsoldiers;i++) {
soldiers.add(new Soldier(this));
}
}
}
Judging by your other code, this sort of pattern will be useful in your Game object as well.
I want to be able to create a for loop like this
For(each booking)
sounds simple for all you experts out there, but ive tried researching how to do this,
and its left me a little confused,
I assume id need a for each loop, which would be something like this
for (type var : coll) {
body-of-loop
}
This program creates a new booking and then allows the user to enter the details into the program of that booking, I have named this B1. IS it that value you enter into the for loop?
I know ill get rated down on this, but i dont understand how i get it to loop for each booking.
Thanks for the quick answers, Ive written some code which ill provide now. Hopefully it will make it easier to see.
Booking Class
public class Booking
{
private int bookingId;
private String route;
private double startTime;
private String bookingDate;
public Booking()
{
bookingId = 0000;
route = "No Route Entered";
startTime = 0.00;
bookingDate = "No Date entered";
}
public int getBookingId()
{
return bookingId;
}
public String getRoute()
{
return route;
}
public double getStartTime()
{
return startTime;
}
public String getBookingDate()
{
return bookingDate;
}
public void setBookingId(int bookingId)
{
this.bookingId = bookingId;
}
public void setRoute(String route)
{
this.route = route;
}
public void setStartTime(double startTime)
{
this.startTime = startTime;
}
public void setBookingDate(String bookingDate)
{
this.bookingDate = bookingDate;
}
public Booking(int bookingId, String route, double startTime, String bookingDate)
{
setBookingId(bookingId);
setRoute(route);
setStartTime(startTime);
setBookingDate(bookingDate);
}
public String toString()
{
return "BookingId: " + getBookingId() + "\nRoute: " + getRoute() + "\nStart Time: " + getStartTime() +
"\nBooking Date: " + getBookingDate();
}
}
Main Class
import java.util.*;
public class Main {
public static void main(String[] args) {
//<editor-fold defaultstate="collapsed" desc="Creates new Student and booking">
Student s1 = new Student();
Booking b1 = new Booking();
s1.setStudentId(Integer.parseInt(JOptionPane.showInputDialog("Enter ID for Student: [0001]")));
s1.setFname(JOptionPane.showInputDialog("Enter first name of Student: "));
s1.setLname(JOptionPane.showInputDialog("Enter last name of Student: "));
s1.setAddress(JOptionPane.showInputDialog("Enter address for Student: "));
s1.setPhoneNo(JOptionPane.showInputDialog("Enter phone number for Student: "));
s1.setOtherDetails(JOptionPane.showInputDialog("Enter other details for Student: [Glasses?]"));
b1.setBookingId(0002);
b1.setStartTime(Double.parseDouble(JOptionPane.showInputDialog("Enter Start time for Booking: [1200]")));
b1.setBookingDate(JOptionPane.showInputDialog("Enter Date for Booking: [01-JAN-12]"));
//</editor-fold>
//For Each Booking
}
}
}
List <Booking> allBookings = new ArrayList<Booking>();
//fill your AllBookings with data
for(Booking b:allBookings){
body of loop // b is your actual Booking Object
}
Something like this would do your work.
You will need an Booking Class, and some data stored in your AllBookings Array List. With you ensure that only Booking Objects can be placed within that Array List.
But back to the For each loop.
The first part (Booking) defines which Object-type is placed in
the list,array or what you want to compute through. Note: You could also place Object instead of Booking since everything is an Object, but I would not recommend you to do that.
The second one (b) is the name of the variable which stands for
the actual element in your list, when iterating over it.
And the third and final part (AllBookings) is your Collection or Array where all your Objects are placed in.
Java Documentation for For-Each Loops:
http://docs.oracle.com/javase/1.5.0/docs/guide/language/foreach.html
You got the syntax right, you just need to pass a collection (or an array) of the objects to the loop:
// bookings is Booking[] or a collection of Booking objects, like List<Booking>
for (Booking b : bookings)
{
// do whatever you need to do with b
}
Type is the name of the type of your object: the thing you'd use to declare it. E.G. Booking.
var is the name of the placeholder variable, which will assume the value of each element that you loop over in the collection. This can be whatever you want.
coll is the name of the collection you want to loop over. It sounds like maybe you called this B1.
So you would use
for (Booking booking : B1){
//body
}
What is booking? foreach loops are used for Array Iteration
I'm assuming this is what you're trying to do, lets say booking is an array of type String[] (i can edit my answer if it's something else)
String[] booking = new String[]{"Hello", "How are You", "Goodbye"};
for (String s: booking)
{
System.out.println(s);
}
for (int i=0; i < booking.length; i++)
{
System.out.println(booking[i]);
}
Produces the following output:
Hello
How are You
Goodbye
Hello
How are You
Goodbye
If you have a collection of type Foo like this:
List<Foo> someList = getSomeList();
Then to loop you can do:
for(Foo myFoo : someList){
System.out.println("I have a foo : "+myFoo);
}
I don't fully understand what you're asking in the paragraph where you mention B1, as what you're describing doesn't seem to require looping at all.
But in general, the for-each loop works the way you've described. Note that the right hand variable is called coll - this is because it needs to be some sort of collection of elements (strictly something that implements Iterable). So if you have e.g. a List<Booking>, you could loop over all of the bookings in this list in turn as follows:
List<Booking> bookings = ...; // populated somehow, or passed in, whatever
for (Booking b : bookings) {
// Do what you want to b, it will be done in turn to each booking in the list
// For example, let's set the hypothetical last updated date to now
b.setLastUpdated(new Date());
}
// At this point all bookings in the list have had their lastUpdated set to now
Going back to what you described:
This program creates a new booking and then allows the user to enter the details into the program of that booking, I have named this B1.
It sounds like you have a booking. Are you sure you need a loop for just one booking? A loop involves performing the same actions on a bunch of different objects; what is it you want to loop over?