Question

尝试解决此编译错误，但无法理解它为什么显示。在一个类（类 - 帐户）中，我定义了一个产品数组：

private Product[] productList;          //List of products for a customer

并写了这个函数：

//Prints all products entered to the account
public void printAllProducts()
{
    int i = 0;
    while (i<this.productCounter)
    {
        printProduct(this.productList[i]);
        i++;
    }
}

当然也在Account类中写了一个printAllProduct函数：

//print specific product
public void printProduct(Product printMe)
{
    System.out.println("in printProduct");
}

但是不断收到编译错误：

The method printProduct(Product) is undefined for the type Account

这是完整的“帐户”类：

package Q2;
import java.util.Scanner;

public class Tester {

    public static void main(String[] args) 
    {
        int[] x;
        Scanner scan = new Scanner(System.in);
        System.out.println("Hello");
        System.out.println("-------------------------");

        System.out.print("Enter the amount the Cashier start with or 0 for Zero amount to start with: ");
        int startAmount = scan.nextInt();

        Cashier newCashier; //create new cashier object with or without a start amount
        if (startAmount>0)
        {
            newCashier = new Cashier(startAmount);
        }
        else
        { 
            newCashier = new Cashier();
        }

        System.out.print("Enter new Customer name: "); //create a new customer
        String name = scan.next();
        Account newAccount = new Account(name);

        int hasMore = 1; // New customer has at least 1 product, when hasMore = 0 purchase has finish and customer has no more products to buy
        do
        {
            newAccount.addNewProduct();

            //checking if there are more products for this customer
            System.out.println("Enter 1 if the customer has another product or 0 to finish purchase");
            hasMore = scan.nextInt();
        } while (hasMore!=0);


        newAccount.printAllProducts(); //Check method that prints all products for a customer


    }
}

这是完整的“产品”类：

package Q2;

import java.util.Scanner;

//Class for product
public class Product 
{
    private String name;            //name of a product 
    private int amount;             //amount from a given product
    private int price;              //price of a given product

    public Product()
    {
        Scanner scan = new Scanner(System.in);

        System.out.print("Enter the name of the product: "); //Start getting details about new product
        this.name = scan.next();
        System.out.print("Enter the amount: ");
        this.amount = scan.nextInt();
        System.out.print("Enter the price: ");
        this.price  = scan.nextInt();
    }


    //print specific product
    public void printProduct(Product printMe)
    {
        System.out.println("in PrintMe");
    }
}

Answer 1

你自己说：

当然在类Product
中写了一个printAllProduct函数

所以你需要使用

Product product = this.productList[i]; product.printProduct(this.productList[i]);

这表明存在设计问题。为什么Product类中的方法printProduct()会将另一个Product作为参数？它应该只是

Product product = this.productList[i]; product.print();

print()方法会打印出被调用的产品（例如this）。

Answer 2

好我成功修复它现在它的工作原理，我真的不明白为什么它没有按照我写的第一种方式工作。为什么我不能只使用（）中的参数启动一个函数，并且必须处理＆＃34;这个。＆＃34;

这是有效的代码：

//Prints all products entered to the account
public void printAllProducts()
{
    int i = 0;
    Product ProductToPrint;
    do
    {
        ProductToPrint = this.productList[i];
        ProductToPrint.printProduct(); 
        i++;
    }while (i<this.productCounter);
}

编译错误＆＃34;该方法未定义类型＆＃34;

2 个答案: