方法字符串和编译器问题发票

Question

这就是我想要做的

    Making·a·new·object·of·class·Invoice:↵Enter 

·the·part·number:32-RJK-45↵Enter 

·the·part·description:Phillips-Screw↵Enter 

·the·Quantity·of·Items:20↵Enter·

 the·Price·Per·Item·with·cents·in·decimals:↵4.50↵↵

 Invoice·price·and·amount·together:↵

我尝试以多种方式使用编译器，使用字符串、双精度数和整数作为数量。

这是我的发票页

package week2chapter3;

public class Invoice {

    private String partNumber; // instance variable

    private String partDescription; // instance variable

    private double priceperitem; // double va1rible

    private int itemBeingPurchesed;// used to total

    private double invoiceAmount;// double that adds invoice amount

    // Part Number

    public Invoice (String partNumber,String partDescription,double priceperitem,

            int itemBeingPurchesed,double invoiceAmount) 

    {this.partNumber = partNumber;// assign it to instance variable name

     // method to get the part number

    }

    {this.partDescription = partDescription;// assign it to instance variable name

     // method to get the part number

    }

    // Part Price

    // validate that the priceperitem is greater than 0.0; if it is not,

    // instance variable priceperitem keeps its default initial value of 0.0

    public void setpriceperitem(double priceperitem) {

        if (priceperitem > 0.0) {// if the balance is valid

            this.priceperitem = priceperitem; // assign it to instance variable balance

        }

    }

我收到几个错误。当我修复一个问题时，我得到未定义的构造函数，当我修复它时，我在我的源页面中得到一个错误，当我修复这些问题时，我得到格式错误。现在 partnumber 在测试页上被读取为错误，而 partDescription 被读取为未定义。

Answer 1

这修复了您代码中的“错误”，但您的代码无法理解，我无法为您提供更多帮助。    public class getInvoiceAmount { public static void main(String[] args) {    Invoice invoice1 = new Invoice();    Invoice invoice2 = new Invoice();    Invoice invoice3 = new Invoice();    Invoice invoice4 = new Invoice();    // display initial balance of each object    System.out.printf("Part number is: %s\n", invoice1.getpartNumber());    System.out.printf("Part description: %s\n", invoice2.getpartDescription());    System.out.printf("Part price: %.2f\n", invoice3.getpriceperitem());    System.out.printf("Part number is: %d\n", invoice4.getitemBeingPurchesed());    // create a Scanner to obtain input from the command window    Scanner input = new Scanner(System.in);    System.out.print("Enter the Part number:"); // prompt    String partNumber = input.nextLine(); // obtain user input    invoice1.setPartNumber( partNumber);    System.out.print("Enter the part description:"); // prompt    String partDescription = input.nextLine(); // obtain user input    System.out.print("Enter the quantity of items :"); // prompt    int itemBeingPurchesed = input.nextInt(); // obtain user input    System.out.print("Enter the pric per item·with cents in decimalse:"); // prompt    double priceperitem = input.nextDouble(); // obtain user input    System.out.printf("Toatal for items: %.2f\n", invoice1.getinvoiceAmount());    }}class Invoice {    private String partNumber; // instance variable    private String partDescription; // instance variable    private double priceperitem; // double va1rible    private int itemBeingPurchesed;// used to total    private double invoiceAmount;// double that adds invoice amount    public Invoice(){    }    // Part Number    public Invoice (String partNumber,String partDescription,double priceperitem,            int itemBeingPurchesed,double invoiceAmount)    {this.partNumber = partNumber;// assign it to instance variable name     // method to get the part number    }    {this.partDescription = partDescription;// assign it to instance variable name     // method to get the part number    }    // Part Price    // validate that the priceperitem is greater than 0.0; if it is not,    // instance variable priceperitem keeps its default initial value of 0.0    public void setpriceperitem(double priceperitem) {        if (priceperitem > 0.0) {// if the balance is valid            this.priceperitem = priceperitem; // assign it to instance variable balance        }    }    // Item purchased    // validate that the itemBeingPurchesed is greater than 0; if it is not,    // instance variable itemBeingPurchesed keeps its default initial value of 0    public void setitemBeingPurchesed(int itemBeingPurchesed) {        if (itemBeingPurchesed > 0) {// if the balance is valid            this.itemBeingPurchesed = itemBeingPurchesed;// assign it to instance variable balance        }    }    // getInvoiceAmount multiply the total if nothing or negative it sets to 0    public void invoiceAmount(double invoiceAmount) {        if (invoiceAmount > 0) {// if the balance is valid            invoiceAmount = itemBeingPurchesed * priceperitem; // assign it to instance variable balance        }    }    public void setPartNumber(String part_number){        partNumber = part_number;    }    // method that returns the partDescription    public String getpartNumber() {        return partNumber;    }    // method that returns the partDescription    public String getpartDescription() {        return partDescription;    }    // method returns the account priceperitem    public double getpriceperitem() {        return priceperitem;    }    public int getitemBeingPurchesed() {        return itemBeingPurchesed;    }    // method returns the account priceperitem    public double getinvoiceAmount() {        return invoiceAmount;    }}