基本上，该程序应该创建一个高管"圆桌会议"，主席不能更换。我有点几乎知道自己在做什么，我的插入和删除高管的方法已经完成了一半，但我只是试着测试我的代码，看看它是如何运行的，当我输入主席信息时，它就会出错。此外，我根本不确定如何处理ExecutiveList中的removeByCorporation方法。我几乎肯定这个方法几乎都是不正确的，我只是不知道如何删除像这样的循环双链表中的节点。
*不需要帮助我打印方法，我只是还没有掌握它们。
tl；博士：1） 为什么它马上就崩溃了？2） 我确信我的removeByCorporation方法是完全错误的。如果是，关于如何修复它，有什么建议或帮助吗？
这是我遇到麻烦的两个类，如果你想看其他的，请告诉我，我会发布它们，但它们99%都是getter和setter。
一级
public class ExecutiveList {
private ExecutiveNode chair;
ExecutiveNode cursor;
public ExecutiveList() {
}
public ExecutiveList (Executive chairperson) {
chair.setExecutive(chairperson);
chair.left = chair;
chair.right = chair;
}
public void insertLeftOfChair(Executive exec) {
ExecutiveNode newExec = new ExecutiveNode();
newExec.setExecutive(exec);
chair.setLeft(newExec);
}
public boolean insertRightOfExec (Executive exec, String target) {
cursor = chair;
ExecutiveNode newExec = new ExecutiveNode();
do { cursor = cursor.getLeft();
if (cursor.getExecutive().equals(exec)) {
newExec.setExecutive(exec);
cursor.getRight().setLeft(newExec);
newExec.setLeft(cursor);
newExec.setRight(cursor.getRight());
cursor.setRight(newExec);
return true;
}
else {
return false;
}
} while (cursor.getExecutive().getExecutiveName() != target);
}
public boolean insertLeftOfExec (Executive exec, String target) {
cursor = chair;
ExecutiveNode newExec = new ExecutiveNode();
do { cursor = cursor.getLeft();
if (cursor.getExecutive().equals(exec)) {
newExec.setExecutive(exec);
cursor.getLeft().setRight(newExec);
newExec.setRight(cursor);
newExec.setLeft(cursor.getRight());
cursor.setLeft(newExec);
return true;
}
else {
return false;
}
} while (cursor.getExecutive().getExecutiveName() != target);
}
public boolean removeTargetExec(String name) {
if (chair.equals(name)) {
return false;
}
else {
return false;
}
}
public int removeByCorporation(String corporation) {
int removed = 0;
cursor = chair;
do {
if (cursor.getExecutive().getCompanyName().equals(corporation)) {
cursor.setExecutive(null);
cursor.getLeft();
removed = removed + 1;
}
} while (removed > 0);
return removed;
}
public void printByCorporation(String corporation) {
}
public void printAllClockwise() {
}
public void printAllCounterClockwise() {
}
}
二级
import java.util.Scanner;
public class MeetingManager {
public static void main(String[] args) {
// scanner to read the users input
Scanner input = new Scanner(System.in);
// strings to pass information about the chairperson
String chairpersonName;
String chairpersonCompany;
// strings to pass information about executives other
// than the chairperson
String execName;
String execCompany;
String target;
// holds information on whether on not an operation
// was successful and how many executives were removed
// for the remove by corporation command.
boolean success;
int numRemoved = 0;
// prompts the user for information about the chairperson
// and sets it to an executive object name chairperson
System.out.println("Enter the name of the chairperson: ");
chairpersonName = input.next();
if (chairpersonName.length() < 1) {
System.out.println("Please enter a full name");
}
System.out.println("Enter the company of the chairperson: ");
chairpersonCompany = input.next();
if (chairpersonCompany.length() < 1) {
System.out.println("Please enter a full name");
}
Executive chairperson = new Executive(chairpersonName, chairpersonCompany);
// creates a new ExecutiveList object and passes information
// about the chairperson
ExecutiveList list = new ExecutiveList(chairperson);
// for loop to repeatedly print the menu and take instructions
// from the user until they choose to exit.
for (int i = 1; i > 0; i++) {
ShowMenu();
String option = input.next();
// error message for improper input
if (option.length() > 3) {
System.out.println("You can only enter one option");
}
// insert left of chairperson
else if (option.toUpperCase().equals("ILC")) {
System.out.println("Enter the executives name: ");
execName = input.next();
System.out.println("Enter the executives company: ");
execCompany = input.next();
Executive newGuy = new Executive(execName, execCompany);
list.insertLeftOfChair(newGuy);
System.out.println("Insertion successful.");
}
// insert left of executive
else if (option.toUpperCase().equals("ILE")) {
System.out.println("Enter the executives name: ");
execName = input.next();
System.out.println("Enter the executives company: ");
execCompany = input.next();
Executive newGuy = new Executive(execName, execCompany);
System.out.println("Enter the name of the target executive: ");
target = input.next();
success = list.insertLeftOfExec(newGuy, target);
if (success == true) {
System.out.println("Insertion successful.");
}
else {
System.out.println("The executive could not be inserted.");
}
}
// insert right of executive
else if (option.toUpperCase().equals("IRE")) {
System.out.println("Enter the executives name: ");
execName = input.next();
System.out.println("Enter the executives company: ");
execCompany = input.next();
Executive newGuy = new Executive(execName, execCompany);
System.out.println("Enter the name of the target executive: ");
target = input.next();
success = list.insertRightOfExec(newGuy, target);
if (success) {
System.out.println("Insertion successful.");
}
else {
System.out.println("The executive could not be inserted.");
}
}
// remove target executive
else if (option.toUpperCase().equals("RTE")) {
System.out.println("Enter the name of the executive to remove: ");
execName = input.next();
success = list.removeTargetExec(execName);
if (execName.equals(chairpersonCompany))
list.removeTargetExec(execName);
if (success) {
System.out.println(execName + " has been removed from the meeting.");
}
else {
System.out.println(execName + " could not be found.");
}
}
// remove by corporation
else if (option.toUpperCase().equals("RBC")) {
System.out.println("Enter the name of the corporation to remove: ");
execCompany = input.next();
numRemoved = list.removeByCorporation(execCompany);
if (execCompany.equals(chairperson.getCompanyName())) {
System.out.println("Invalid command: cannot remove all employees from the chairperson's corporation");
}
else if (numRemoved < 1) {
System.out.println("That corporation could not be found and no executives were removed.");
}
else {
System.out.println(numRemoved + " executive(s) from " + execCompany + " have been removed from the meeting.");
}
}
// prints by corporation
else if (option.toUpperCase().equals("PBC")) {
System.out.println("Enter the name of a corporation to display: ");
execCompany = input.next();
list.printByCorporation(execCompany);
}
// prints all counter-clockwise
else if (option.toUpperCase().equals("PCC")) {
list.printAllCounterClockwise();
}
// prints all clockwise
else if (option.toUpperCase().equals("PCL")) {
list.printAllClockwise();
}
else if (option.toUpperCase().equals("EXT")) {
System.out.println("Terminating program...");
break;
}
// Error message
else {
System.out.println("Please select a valid option.");
}
}
}
// displays menu and prompts user for input
public static void ShowMenu() {
System.out.println("nILC) Insert an executive to the left of the chairpersonnILE) Insert an executive to the left of a given executivenIRE) Insert an executive to the right of a given executivenRTE) Remove Target Executive");
System.out.println("RBC) Remove By CorporationnPBC) Print By CorporationnPCC) Print all in counter-clockwise ordernPCL) Print all in clockwise ordernEXT) Exit the programnnSelect a menu option: ");
}
}
最后，感谢任何以任何形式提供任何建议、建议或实际帮助的人。我知道人们在看到家庭作业问题时会因为某种原因而生气，因为他们认为学生是在要求他们"为我做家庭作业"，但我不是在做这件事。我只是想要任何建议或提示，我并不是要求你帮我填空并解决所有问题（并不是说我会反对：P）。谢谢
在removeByCorporation方法中，您只是将executive设置为null，但考虑到这是一个双链表，您不认为需要设置上一个和下一个executive的引用，这样双链表就不会断开。
诀窍是确保在每次操作中，都更新正在更改的项和引用它的另外两个项（在双链接列表中，引用它的两个也是它引用的两个）。
检查你的每种方法，并确保在每种方法中，每次更改都更新4个字段——主题中有两个，从主题链接的两个字段中各有一个。