I'm working on a project with a friend; we're trying to create an airplane project using a Passenger class for passengers, Airplane class to add in passengers and create the airplane, and a driver class. We've run into an issue where when we add in all the passengers to the airplane and print all details of the airplane, printed values are capturing only the last passenger's information. We're trying to get this for every passenger. Here is the code:
Passenger
public class Passenger {
private String name;
private int birthYear;
private double weight;
private char gender;
private int numCarryOn;
//Default constructor
public Passenger(){
name = "";
birthYear = 1900;
weight = 0.0;
gender = 'u';
numCarryOn = 0;
}
//Alt default constructor
public Passenger(String newName, int newBirthYear, double newWeight, char newGend, int newNumCarryOn){
this.setName(newName);
this.setBirthYear(newBirthYear);
this.setWeight(newWeight);
this.setGender(newGend);
this.setNumCarryOn(newNumCarryOn);
}
//Calculate age
public int calculateAge(int currentYear){
int age = 0;
if (currentYear < birthYear){
return -1;
}
else {
age = currentYear - birthYear;
}
return age;
}
//Gain weight
public void gainWeight(){
weight = 1;
}
//Gain weight based on input
public void gainWeight(double pounds){
if (weight > 0){
weight = weight pounds;
}
}
//Get birthYear
public int getBirthYear(){
return birthYear;
}
//Get gender
public char getGender(){
return gender;
}
//Get name
public String getName(){
return name;
}
//Get weight
public double getWeight(){
return weight;
}
//Get numCarryOn
public int getNumCarryOn(){
return numCarryOn;
}
//isFemale
public boolean isFemale(){
if (gender == 'f'){
return true;
}
else {
return false;
}
}
//isMale
public boolean isMale(){
if (gender == 'm'){
return true;
}
else {
return false;
}
}
//loseWeight
public void loseWeight(){
if (weight > 0){
weight -= 1;
}
}
//lose weight by value
public void loseWeight(double weight2lose){
if (weight - weight2lose >= 0){
weight -= weight2lose;
}
}
//print
public void printDetails(){
System.out.printf("Name: s | Year of Birth: M | Weight: .2f | Gender: %c | NumCarryOn: -\n", name, birthYear, weight, gender, numCarryOn);
}
//setGender
public void setGender(char newGender){
if (newGender == 'f' || newGender == 'm') {
this.gender = newGender;
} else {
this.gender = 'u';
}
}
//setName
public void setName(String newName){
name = newName;
}
//setBirthYear
public void setBirthYear(int newBY){
birthYear = newBY;
}
//setWeight
public void setWeight(double newWeight){
if (newWeight < 0){
weight = -1;
}
else {
weight = newWeight;
}
}
//setNumCarryOn
public void setNumCarryOn(int newNumCarryOn){
if (newNumCarryOn < 0){
numCarryOn = 0;
}
else if (newNumCarryOn > 2){
numCarryOn = 2;
}
else {
numCarryOn = newNumCarryOn;
}
}
}
Airplane
public class Airplane {
private Passenger[] passengers;
private String airplaneName;
private int numPassengers;
public int count = 0;
//default constructor
public Airplane(){
airplaneName = "";
passengers = new Passenger[100];
numPassengers = 0;
}
//default constructor with String input
public Airplane(String otherairplaneName){
airplaneName = otherairplaneName;
passengers = new Passenger[100];
numPassengers = 0;
}
//default constructor with int input
public Airplane(int otherArraySize){
airplaneName = "";
if (otherArraySize < 0){
otherArraySize = 0;
}
passengers = new Passenger[otherArraySize];
numPassengers = 0;
}
//default constructor with String and int input
public Airplane(String otherAirplaneName, int otherArraySize){
airplaneName = otherAirplaneName;
if (otherArraySize < 0){
otherArraySize = 0;
}
passengers = new Passenger[otherArraySize];
numPassengers = 0;
}
//add a passenger
public void addPassenger(Passenger a){
for (int i = 0; i < passengers.length; i ){
passengers[i] = a;
}
}
//resize array for new passengers
private void resizePassengerArray(){
passengers = new Passenger[passengers.length * 2];
}
//get a passenger
public Passenger getPassenger(int passengerIndex){
return passengers[passengerIndex];
}
//getNumPassengers
public int getNumPassengers() {
return count;
}
//getFirstPassenger
public Passenger getFirstPassenger(){
return passengers[0];
}
//getLastPassenger
public Passenger getLastPassenger(){
return passengers[passengers.length - 1];
}
//getPassengers**
public Passenger[] getPassengers(){
return passengers;
}
//setAirplaneName
public void setAirplaneName(String newAirplaneName){
airplaneName = newAirplaneName;
}
//printAllDetails
public void printAllDetails(){
System.out.printf("AirplaneName: s | Number of Passengers: M | Airplane Size: M\n", airplaneName, count, passengers.length);
for (int i = 0; i < count; i ){
System.out.printf("Name: s | Year of Birth: M | Weight: .2f | Gender: %c\n", passengers[i].getName(), passengers[i].getBirthYear(), passengers[i].getWeight(), passengers[i].getGender());
}
}
//removePassenger
public Passenger removePassenger(int passengerIndex){
if (passengerIndex != passengers.length - 1){
for (int i = passengerIndex; i < passengers.length - 1; i ){
passengers[i] = passengers[i 1];
}
}
return passengers[passengerIndex];
}
//remove all passengers
public void removeAllPassengers(){
passengers = new Passenger[100];
}
//total weight passengers
public double getTotalWeightOfAllPassengers(){
double weight = 0.0;
for (int i = 0; i < passengers.length; i ){
weight = passengers[i].getWeight();
}
return weight;
}
//avg weight passengers
public double getAverageWeightOfAllPassengers(){
double avg = this.getTotalWeightOfAllPassengers() / numPassengers;
return avg;
}
//num elements above weight
public int getNumberOfPassengersAboveWeight(double weight){
int sum = 0;
for (int i = 0; i < passengers.length; i ){
if (passengers[i].getWeight() > weight){
sum = 1;
}
}
return sum;
}
//num elements below weight
public int getNumberOfPassengersBelowWeight(double weight){
int sum = 0;
for (int i = 0; i < passengers.length; i ){
if (passengers[i].getWeight() < weight){
sum = 1;
}
}
return sum;
}
//increase weight of passengers
public void increaseWeightOfAllPassengers(){
for (int i = 0; i < passengers.length; i ){
passengers[i].gainWeight();
}
}
//increase weight of passengers with weight input
public void increaseWeightOfAllPassengers(double increaseAmount){
for (int i = 0; i < passengers.length; i ){
passengers[i].gainWeight(increaseAmount);
}
}
}
Driver
public class RunAirplane {
public static void main(String[] args) {
Airplane a1 = new Airplane("Flight 1", 100);
Passenger p1 = new Passenger("Albert", 1879, 198.5, 'm', 2);
Passenger p2 = new Passenger("Grace", 1906, 105, 'f', 1);
Passenger p3 = new Passenger("Tim", 1955, 216.3, 'm', 2);
Passenger p4 = new Passenger("Steve", 1955, 160, 'm', 2);
Passenger p5 = new Passenger("Sergey", 1973, 165.35, 'm', 1);
a1.addPassenger(p1);
a1.count = 1;
a1.addPassenger(p2);
a1.count = 1;
a1.addPassenger(p3);
a1.count = 1;
a1.addPassenger(p4);
a1.count = 1;
a1.addPassenger(p5);
a1.count = 1;
a1.printAllDetails();
//How it should work starting with name
System.out.println(p1.getName());
System.out.println(p2.getName());
}
}
Here's a screenshot of the incorrect code: https://imgur.com/TGc0FQa
CodePudding user response：
The addPassenger() method is overwriting every element in the array:
public void addPassenger(Passenger a){
for (int i = 0; i < passengers.length; i ){
passengers[i] = a;
}
}
It should just set the one at the next available index, which happens to be count:
public void addPassenger(Passenger a){
passengers[count ] = a;
}
This also gives you better encapsulation, as you don't have to expose and increment count externally.
CodePudding user response：
this
public void addPassenger(Passenger a){
for (int i = 0; i < passengers.length; i ){
passengers[i] = a;
}
}
Produce every time a Passenger Array full with the same Passenger. Perhaps this might solve the problem.
public void addPassenger(Passenger a){
for (int i = 0; i < passengers.length; i ){
if((passengers[i-1] !=null)&&((passengers[i] ==null))
{ passengers[i] = a; }
}
}
A better implementation could be with ArrayList
Airplane
public class Airplane {
private ArrayList<Passenger> passengers;
private String airplaneName;
private int numPassengers;
public int count = 0;
//default constructor
public Airplane(){
airplaneName = "";
passengers = new ArrayList();
numPassengers = 0;
}
//default constructor with String input
public Airplane(String otherairplaneName){
airplaneName = otherairplaneName;
passengers = new ArrayList();
numPassengers = 0;
}
//default constructor with String and int input
public Airplane(String otherAirplaneName){
airplaneName = otherAirplaneName;
passengers = new ArrayList();
numPassengers = 0;
}
//add a passenger
public void addPassenger(Passenger a){
passengers.add(a);
}
//get a passenger
public Passenger getPassenger(int passengerIndex){
return passengers[passengerIndex];
}
//getNumPassengers
public int getNumPassengers() {
return count;
}
//getFirstPassenger
public Passenger getFirstPassenger(){
return passengers.get(0);
}
//getLastPassenger
public Passenger getLastPassenger(){
return passengers.get(passengers.size() - 1);
}
//getPassengers**
public ArrayList<Passenger> getPassengers(){
return passengers;
}
//setAirplaneName
public void setAirplaneName(String newAirplaneName){
airplaneName = newAirplaneName;
}
//printAllDetails
public void printAllDetails(){
System.out.printf("AirplaneName: s | Number of Passengers: M | Airplane Size: M\n", airplaneName, count, passengers.size());
for (int i = 0; i < count; i ){
System.out.printf("Name: s | Year of Birth: M | Weight: .2f | Gender: %c\n", passengers.get(i).getName(), passengers[i].get(i).getBirthYear(), passengers[i].get(i).getWeight(), passengers[i].get(i).getGender());
}
}
//removePassenger
public Passenger removePassenger(int passengerIndex){
passengers.remove(passengerIndex);
return passengers.get(passengerIndex);
}
//remove all passengers
public void removeAllPassengers(){
passengers = new ArrayList();
}
//total weight passengers
public double getTotalWeightOfAllPassengers(){
double weight = 0.0;
for (int i = 0; i < passengers.size(); i ){
weight = passengers.get(i).getWeight();
}
return weight;
}
//avg weight passengers
public double getAverageWeightOfAllPassengers(){
double avg = this.getTotalWeightOfAllPassengers() / numPassengers;
return avg;
}
//num elements above weight
public int getNumberOfPassengersAboveWeight(double weight){
int sum = 0;
for (int i = 0; i < passengers.size(); i ){
if (passengers.get(i).getWeight() > weight){
sum = 1;
}
}
return sum;
}
//num elements below weight
public int getNumberOfPassengersBelowWeight(double weight){
int sum = 0;
for (int i = 0; i < passengers.size(); i ){
if (passengers.get(i).getWeight() < weight){
sum = 1;
}
}
return sum;
}
//increase weight of passengers
public void increaseWeightOfAllPassengers(){
for (int i = 0; i < passengers.size(); i ){
passengers.get(i).gainWeight();
}
}
//increase weight of passengers with weight input
public void increaseWeightOfAllPassengers(double increaseAmount){
for (int i = 0; i < passengers.size(); i ){
passengers.get(i).gainWeight(increaseAmount);
}
}
}
CodePudding user response：
The issue is in the method addPassenger. You are replacing always the first element.
You can fix in this way:
public void addPassenger(Passenger a){
passengers[count] = a;
count
}
For better implementation, you can remove count and use numPassengers.
Therefore the method becomes:
public void addPassenger(Passenger a){
passengers[numPassengers] = a;
numPassengers
}
and the main class:
public class RunAirplane {
public static void main(String[] args) {
Airplane a1 = new Airplane("Flight 1", 100);
Passenger p1 = new Passenger("Albert", 1879, 198.5, 'm', 2);
Passenger p2 = new Passenger("Grace", 1906, 105, 'f', 1);
Passenger p3 = new Passenger("Tim", 1955, 216.3, 'm', 2);
Passenger p4 = new Passenger("Steve", 1955, 160, 'm', 2);
Passenger p5 = new Passenger("Sergey", 1973, 165.35, 'm', 1);
a1.addPassenger(p1);
a1.addPassenger(p2);
a1.addPassenger(p3);
a1.addPassenger(p4);
a1.addPassenger(p5);
a1.printAllDetails();
//How it should work starting with name
System.out.println(p1.getName());
System.out.println(p2.getName());
}
}
For the best implementation, you can use List instead of an array for the field passengers:
private List<Passenger> passengers;
public Airplane(){
airplaneName = "";
passengers = new ArrayList<>();
}
public void addPassenger(Passenger a){
passengers.add(a);
}
You can remove the numPassengers and use size:
public int getNumPassengers() {
return passengers.size();
}