我应该创建一个接受客户ID的方法，然后在找到该ID的情况下返回数组中的索引。使用该方法时，只能输入整数ID。
我使用了迭代的二进制搜索，以便能够搜索我的客户数组列表。但是问题在于，将Customer数组与Integer进行比较时，它被操作数类型卡住了。我试图将方法的类型更改为static，CustomerList，Customer等。但这根本不影响它。
代码中的cl是我在课程开始时创建的公共字段。
作为->公共客户[] cl;
**public class Person {
private String firstName;
private String lastName;
private String address;
private String city;
private String state;
private String zipCode;
public Person(String firstName, String lastName, String address, String city, String state, String zipCode) {
this.firstName = firstName;
this.lastName = lastName;
this.address = address;
this.city = city;
this.state = state;
this.zipCode = zipCode;
}
protected Person() {
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getCity() {
return this.city;
}
public void setCity(String city) {
this.city = city;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getZipCode() {
return zipCode;
}
public void setZipCode(String zipCode) {
this.zipCode = zipCode;
}
@Override
public String toString() {
return "FirstName: " + firstName + "\nLastName: " + lastName + "\nAddress: " + address + "\nCity: " + city + "\nState: " + state + "\nZipCode: " + zipCode;
}
public String toCSV() {
return this.firstName + "," + this.lastName + "," + this.address + "," + this.city
+ "," + this.state + "," + this.zipCode;
}
public void copy(Person p) {
firstName = p.firstName;
lastName = p.lastName;
address = p.address;
city = p.city;
state = p.state;
zipCode = p.zipCode;
}
public void copy(String firstName, String lastName, String address, String city, String state, String zipCode) {
this.firstName = firstName;
this.lastName = lastName;
this.address = address;
this.city = city;
this.zipCode = zipCode;
}
@Override
public Person clone() {
Person p = new Person(this.firstName, this.lastName, this.address, this.city, this.state, this.zipCode);
return p;
}
}**
**public class Customer extends Person{
private int customerID;
private double grossSales;
public Customer(int customerID, double grossSales, String firstName, String lastName, String address, String city, String state, String zipCode) {
super(firstName, lastName, address, city, state, zipCode);
this.customerID = customerID;
this.grossSales = grossSales;
}
public Customer(String s, int customerID, double grossSales, String firstName, String lastName, String address, String city, String state, String zipCode) {
super(firstName, lastName, address, city, state, zipCode);
copyCSV(s);
}
protected Customer() {
}
public int getCustomerID() {
return customerID;
}
public void setCustomerID(int customerID) {
this.customerID = customerID;
}
public double getGrossSales() {
return grossSales;
}
public void setGrossSales(double grossSales) {
this.grossSales = grossSales;
}
@Override
public String toString() {
return "CustomerID: " + customerID + "\nGrossSales: " + grossSales + super.toString();
}
public String toCSV() {
return this.customerID + "," + this.grossSales + "," + super.toCSV();
}
public void copy(Customer c) {
super.copy(c);
customerID = c.customerID;
grossSales = c.grossSales;
}
public void copy(int customerId, double grossSales, String firstName, String lastName, String address, String city, String state, String zipCode) {
super.copy(firstName, lastName, address, city, state, zipCode);
this.customerID = customerId;
this.grossSales = grossSales;
}
public Customer clone() {
Customer c = new Customer(this.customerID, this.grossSales, this.getFirstName(), this.getLastName(), this.getAddress(), this.getCity(), this.getState(), this.getZipCode());
return c;
}
public int compareTo(Customer c) {
int returnValue = 0;
if (this.customerID > c.customerID) {
returnValue = -1;
} else if (this.customerID < c.customerID) {
returnValue = 1;
} else {
returnValue = 0;
}
return returnValue;
}
public void copyCSV(String s) {
List<String> list = new ArrayList<>();
String[] a = s.split(",");
list = Arrays.asList(a);
this.copy(Integer.parseInt(list.get(0)), Double.parseDouble(list.get(1)), list.get(2),
list.get(3), list.get(4), list.get(5), list.get(6), list.get(7));
}
}**
public int indexOf(Integer id) {
int min = 0;
int max = cl.length - 1;
while (min <= max) {
int mid = (min + max) / 2;
if (cl[mid] < id) {
min = mid + 1;
} else if (cl[mid] > id) {
max = mid - 1;
} else {
return mid; // target found
}
}
return -(min + 1); // target not found
}
应该接受一个customerID，如果找到，则返回数组中的索引，否则返回插入点。
基本上，我们有一个CSV文件，其中包含客户列表，并且为每个客户分配了一个ID。我们有人员类别和客户类别，我将它们包括在其中并设置所有变量。以及toString和toCSV方法。在最后一个类CustomerList中，有几种方法。尤其是，这个应该采用一个整数，例如1、2、3、4等。如果有人分配了该ID号，它将返回该人在创建的数组中的索引。
但是它被卡在if和else if比较语句中。
答案 0 :(得分：0)
假设一个客户类别，例如：
public class Customer {
private int id;
private String name;
public Customer() {
}
public Customer(int id, String name) {
this.id = id;
this.name = name;
}
public int getId() {
return id;
}
public String getName() {
return name;
}
public void setId(int id) {
this.id = id;
}
public void setName(String name) {
this.name = name;
}
}
您可以通过传递以下两种方式来以静态方法返回客户数组中ID的索引：
public static int indexOf(Customer[] arr, Customer cust) {
int min = 0;
int max = arr.length - 1;
while (min <= max) {
int mid = (min + max) / 2;
if (arr[mid].getId() < cust.getId()) {
min = mid + 1;
} else if (arr[mid].getId() > cust.getId()) {
max = mid - 1;
} else {
return mid; // target found
}
}
return -(min + 1); // target not found
}
您还可以将其转换为非静态方法，并为Customer []对象创建一个类。或者，您可以像这样在您的主要（或任何其他方法）中使用它：
Customer cl1 = new Customer(1234,"John");
Customer cl2 = new Customer(1235,"Khal");
Customer cl3 = new Customer(1236,"John");
Customer[] clArray = {cl1,cl2,cl3};
Customer testCustomer = new Customer(1236,"AnyName");
int index = indexOf(clArray, testCustomer);
System.out.println(index); //Prints 2, which is the location of 1236 in the array
客户当前正在存储名称和ID，可以更改以存储所需的任何值，您只需要编辑构造函数和私有类变量即可。
如果您打算保留信息并经常更改它，我也建议研究ArrayList。数组不是最好的处理方法。
编辑： 根据您的评论，这是CustomerArray类的样子：
public class CustomerArray {
private Customer[] cl;
public CustomerArray() {
}
public CustomerArray(Customer...customers ) {
this.cl = customers;
}
public Customer[] getCl() {
return cl;
}
public void setCl(Customer[] cl) {
this.cl = cl;
}
public int indexOf(int id) {
int min = 0;
int max = cl.length - 1;
while (min <= max) {
int mid = (min + max) / 2;
if (cl[mid].getId() < id) {
min = mid + 1;
} else if (cl[mid].getId() > id) {
max = mid - 1;
} else {
return mid; // target found
}
}
return -(min + 1); // target not found
}
}
然后您就可以在main方法（或任何其他方法）中使用它了，
Customer cl1 = new Customer(1234,"John");
Customer cl2 = new Customer(1235,"Khal");
Customer cl3 = new Customer(1236,"John");
CustomerArray clArray = new CustomerArray(cl1,cl2,cl3);
Customer testCustomer = new Customer(1236,"AnyName");
int index = clArray.indexOf(testCustomer.getId());
System.out.println(index);
因此，基本上，您要声明一个拥有所有客户的CustomerArray。