基本上，这是我的 TelevisionInventory 课程
import java.util.ArrayList;
import java.util.List;
import java.util.Queue;
import java.util.Scanner;
import java.util.Stack;
public class TelevisionInventory {
private List<Television> tvList = new ArrayList<>();
private LinkedList linkedList = new LinkedList();
private Stack<Television> tvStack = new Stack<>();
private Queue<Television> tvQueue = new LinkedList<>();
private Scanner scanner = new Scanner(System.in);
public void runInventorySystem() {
int option;
do {
System.out.println("\nTelevision Inventory System");
System.out.println("1. Add Television");
System.out.println("2. Delete Television");
System.out.println("3. Search and Display");
System.out.println("4. Display All Televisions");
System.out.println("5. Calculate");
System.out.println("6. Move Data to LinkedList");
System.out.println("7. Display data in LinkedList");
System.out.println("8. Move data to Stack");
System.out.println("9. Copy data to Stack");
System.out.println("10. Display data in Stack");
System.out.println("11. Move data to Queue");
System.out.println("12. Copy data to Queue");
System.out.println("13. Display data in Queue");
System.out.println("14. Make an Expression Conversion");
System.out.println("15. Exit");
System.out.print("Select an option: ");
option = scanner.nextInt();
scanner.nextLine();
System.out.println();
switch (option) {
case 1:
addTelevision();
break;
case 2:
deleteTelevision();
break;
case 3:
searchAndDisplay();
break;
case 4:
displayInventory(tvList, "List of Televisions");
break;
case 5:
calculateStats();
break;
case 6:
moveDataToLinkedList();
break;
case 7:
displayLinkedListData();
break;
case 8:
moveDataToStack();
break;
case 9:
copyDataToStack();
break;
case 10:
displayStackData();
break;
case 11:
moveDataToQueue();
break;
case 12:
copyDataToQueue();
break;
case 13:
displayQueueData();
break;
case 14:
expressionConversion();
break;
case 15:
System.out.println("Exiting...");
break;
default:
System.out.println("Invalid option, please try again.");
break;
}
} while (option != 15);
scanner.close();
}
private void addTelevision() {
boolean continueAdding = true;
while (continueAdding) {
System.out.println();
System.out.print("Enter TV ID: ");
int id = scanner.nextInt();
scanner.nextLine();
System.out.print("Enter Brand: ");
String brand = scanner.nextLine();
System.out.print("Enter Size (in inches): ");
int size = scanner.nextInt();
System.out.print("Is it Digital? (true/false): ");
boolean isDigital = scanner.nextBoolean();
System.out.print("Enter Price: ");
double price = scanner.nextDouble();
scanner.nextLine();
Television tv = new Television(id, brand, size, isDigital, price);
tvList.add(tv);
System.out.println("Television added successfully!");
System.out.print("Do you want to add another TV? (true/false): ");
continueAdding = scanner.nextBoolean();
scanner.nextLine();
}
}
private void deleteTelevision() {
System.out.print("Enter TV ID to delete: ");
int id = scanner.nextInt();
boolean found = false;
for (int i = 0; i < tvList.size(); i++) {
if (tvList.get(i).getId() == id) {
tvList.remove(i);
found = true;
System.out.println("Television with ID " + id + " has been removed.");
break;
}
}
if (!found) {
System.out.println("No television with ID " + id + " found.");
}
}
private void searchAndDisplay() {
System.out.print("Enter TV ID or name to search: ");
String input = scanner.nextLine();
Television searchedTv = null;
try {
int id = Integer.parseInt(input);
for (Television tv : tvList) {
if (tv.getId() == id) {
searchedTv = tv;
break;
}
}
} catch (NumberFormatException e) {
for (Television tv : tvList) {
if (tv.getBrand().equalsIgnoreCase(input)) {
searchedTv = tv;
break;
}
}
}
if (searchedTv != null) {
System.out.println("Found Television: " + searchedTv);
} else {
System.out.println("Television not found.");
}
}
private void displayInventory(List<Television> inventory, String type) {
if (inventory.isEmpty()) {
System.out.println(type + " is empty.");
} else {
System.out.println(type + " Inventory:");
inventory.forEach(System.out::println);
}
}
private void displayLinkedListData() {
if (linkedList.isEmpty()) {
System.out.println("LinkedList is empty.");
} else {
System.out.println("LinkedList Inventory:");
System.out.println(linkedList.printList());
}
}
private void calculateStats() {
if (tvList.isEmpty()) {
System.out.println("No Televisions in inventory.");
return;
}
double sum = 0;
double avg;
double min = Double.MAX_VALUE;
double max = Double.MIN_VALUE;
for (Television tv : tvList) {
double price = tv.getPrice();
sum += price;
if (price < min) {
min = price;
}
if (price > max) {
max = price;
}
}
avg = sum / tvList.size();
System.out.println("\nSum: RM " + sum + "\nAverage: RM " + avg + "\nMinimum: RM " + min + "\nMaximum: RM " + max);
}
private void moveDataToLinkedList() {
for (Television tv : tvList) {
linkedList.insertAtBack(tv);
}
tvList.clear();
System.out.println("Data moved to LinkedList successfully.");
}
private void copyDataToStack() {
for (int i = 0; i < linkedList.size(); i++) {
try {
tvStack.push((Television) linkedList.getNext());
} catch (LinkedList.EmptyListException e) {
System.out.println("Error: " + e.getMessage());
}
}
System.out.println("Data copied to Stack successfully.");
}
private void moveDataToStack() {
for (Television tv : tvList) {
tvStack.push(tv);
}
tvList.clear();
System.out.println("Data moved to Stack successfully.");
}
private void displayStackData() {
if (tvStack.isEmpty()) {
System.out.println("Stack is empty.");
} else {
System.out.println("Stack Inventory:");
System.out.println(tvStack);
}
}
private void moveDataToQueue() {
for (Television tv : tvList) {
tvQueue.offer(tv);
}
tvList.clear();
System.out.println("Data moved to Queue successfully.");
}
private void copyDataToQueue() {
for (Television tv : tvList) {
tvQueue.offer(tv);
}
System.out.println("Data copied to Queue successfully.");
}
private void displayQueueData() {
if (tvQueue.isEmpty()) {
System.out.println("Queue is empty.");
} else {
System.out.println("Queue Inventory:");
System.out.println(tvQueue);
}
}
private void expressionConversion() {
System.out.print("Enter infix expression to convert: ");
String infix = scanner.nextLine();
String postfix = PostFixConverter.convertToPostFix(infix);
System.out.println("Postfix Expression: " + postfix);
}
}
这是我的 LinkedList 类
public class LinkedList
{
private Node head, tail, current;
//Default LinkedList Class
public LinkedList() {
head = tail = current = null;
}
//To check whether is the linked list empty
public boolean isEmpty() {
return head == null;
}
// to print data
public String printList()
{
if (isEmpty())
return "( empty list )";
else
return "(" + head + ")";
}
//To add new Object data at the front of the LinkedList
public void insertAtFront(Object data)
{
if(isEmpty())
head = tail = new Node(data);
else
head = new Node(data, head);
}
// Return the number of elements in the list
public int size()
{
int count = 0;
if (isEmpty())
return count;
current = head;
while(current != null)
{
++count;
current = current.next;
}
return count;
}
//To add new Object data at the back of linked list
public void insertAtBack(Object data)
{
if(isEmpty())
head = tail = new Node(data);
else
tail = tail.next = new Node(data);
}
// Return the first element in the linked list
public Object getFirst() throws EmptyListException
{
if(isEmpty())
throw new EmptyListException();
current = head;
return current.data;
}
// Return the next element in the linked list
public Object getNext() {
if (current == null) {
current = head;
} else if (current != tail) {
current = current.next;
}
return current != null ? current.data : null;
}
// Return the last element in the linked list
public Object getLast() throws EmptyListException
{
if(isEmpty())
throw new EmptyListException();
return tail.data;
}
// Remove the first element in the linked list
public Object removeFromFront() throws EmptyListException
{
if(isEmpty())
throw new EmptyListException();
Object d = head.data;
if(head==tail)
head=tail=null;
else
{
Node curr = head;
head = head.next;
curr.next = null;
}
return d;
}
// Remove the last element in the linked list
public Object removeFromBack() throws EmptyListException
{
if(isEmpty())
throw new EmptyListException();
Object d = tail.data;
if(head==tail)
head=tail=null;
else
{
Node curr = head;
while(curr.next != tail)
curr = curr.next;
tail = curr;
curr.next = null;
}
return d;
}
public class EmptyListException extends RuntimeException{
public EmptyListException(){
super("The list is empty");
}
}
}
问题出现在第11行，仅在'<>'部分有错误。我使用的编译器说 “无法推断 LinkedList 的参数类型。原因：不能将 '<>' 与非泛型类 LinkedList 一起使用。”
我认为我需要告诉的另一个线索是 LinkedList 类具有到节点的链接，并且 LinkedList 类是 Queue 类和 Stack 类的父类。 类之间关系图
那么，问题是，有没有办法在不删除 TelevisionInventory 类和 LinkedList 类之间的链接的情况下调试此代码？
我尝试将 import.java.util.LinkedList 添加到 TelevisionInventory 类中。但是，它们之间的联系消失了。
我还尝试删除 LinkedList 类并将所有代码放入 TelevisionInventory 类中。但是，程序变得太混乱了，我不知道将堆栈类和队列类放在哪里。
您的
LinkedListQueue<Television>你可以这样做（通过使用泛型）：
public class LinkedList<T> implements Queue<T> {
...
}
您需要实现为
QueueT public void insertAtBack(T data)
public T getFirst() throws EmptyListException
public T getNext() {
public T getLast() throws EmptyListException
public T removeFromFront() throws EmptyListException
public T removeFromBack() throws EmptyListException
备注：
由于您将 LinkedList 实例分配给 Queue 类型的变量，您将只能访问 Queue 中定义的方法（对于其他方法，您需要首先将类型转换为 LinkedList）。