Question

这是我的班级任务。我一直在输出中得到错误的杂货。在运行代码时，我该如何获得正确的项目？

以下是我目前获得的输出：

购物者姓名：Gary

冰淇淋：5个单位，每个单位4.25美元= 21.25美元

----＆GT;小计= $ 42.5

----＆GT; 7％税= 2.975美元

----＆gt;总计= $ 45.475

购物者名称：莎莉

冰淇淋：2个单位，每个单位4.25美元= 8.5美元

----＆GT;小计= $ 17.0

----＆GT; 7％税= 1.1900000000000002

----＆gt;总计= $ 18.19

购物车类：

public class Cart
{
public String Name;
public int ItemNum;
public double tax;




public Cart(String ShopperName){
    Name = ShopperName;
}
public String getShopperName(){
    return Name;
}
public int getItemNumber(){
    return ItemNum;
}
public void addItem1(GroceryItem GroceryItem, int NumberItem){
    GroceryItem = GroceryItem;
    ItemNum = NumberItem;
}
public void addItem2(GroceryItem GroceryItem, int NumberItem){
    GroceryItem = GroceryItem;
    ItemNum = NumberItem;
}
public double getItemTotal(){
    double item_total = (double) (GroceryItem.getCost()*getItemNumber());
    return item_total;
}
public double getSubtotal(){
    double subtotal = (double) (getItemTotal() + getItemTotal());
    return subtotal;
}
public double getTaxTotal(){
    double tax = .07;
    double taxtotal = (double) (getSubtotal()*tax);
    return taxtotal;
}
public double getTotal(){
    double Total = (double) (getTaxTotal()+getSubtotal());
    return Total;
}
public void printReceipt(){
    System.out.println("Shopper Name: " + getShopperName());
    System.out.println("----------------------");
    System.out.println(GroceryItem.getName()+":"+ getItemNumber()+ " units at $" + GroceryItem.getCost()+" per unit"+ " = $"+ getItemTotal());
    System.out.println(GroceryItem.getName()+":"+ getItemNumber()+ " units at $" + GroceryItem.getCost()+" per unit"+ " = $"+ getItemTotal());
    System.out.println("----> Subtotal = $" + getSubtotal());
    System.out.println("----> 7% tax = $" + getTaxTotal() );
    System.out.println("---->Total = $" + getTotal());
    System.out.println("");
    System.out.println("");
    System.out.println("");
}
}

驱动程序类：

/**
 * Driver for Cart and GroceryItem.
 */
public class Driver
{
public static void main(String[] args)
{
    // create grocery items
    GroceryItem item1 = new GroceryItem("milk", 3.39);
    GroceryItem item2 = new GroceryItem("eggs", 1.75);
    GroceryItem item3 = new GroceryItem("ice cream", 4.25);

    // create new carts
    Cart shopper1 = new Cart("Gary");
    Cart shopper2 = new Cart("Sally");


    // add items to first cart 
    shopper1.addItem1(item2, 1);        //1 "eggs" is being added
    shopper1.addItem2(item1, 5);        //5 "milk" are being added

    // add items to second cart
    shopper2.addItem1(item3, 2);        //2 "ice cream" are being added
    shopper2.addItem2(item2, 2);        //2 "eggs" are being added

    // print cart's receipt
    shopper1.printReceipt();
    shopper2.printReceipt(); 

}
}

Answer 1

这看起来不对：

public void addItem1(GroceryItem GroceryItem, int NumberItem){
    GroceryItem = GroceryItem;
    ItemNum = NumberItem;
}

你正在为自己分配GroceryItem。

addItem2方法相同。

实际上，您的购物车似乎没有办法存放这些物品。看起来你并没有抓住这里的必需品。回到书本我害怕......

Answer 2

您已在addItem方法中将项目分配给自己。声明实例变量并指定您使用this重新分配实例变量。

例如：

public class Cart {
private GroceryItem groceryItem;
...

public void addItem1(GroceryItem groceryItem, int NumberItem){
    this.groceryItem = groceryItem;
    ...

然后在打印结果时，使用实例变量groceryItem。

此外，在java中，成员（变量/方法名称）应位于lower camel case。

将商品添加到购物车时，错误的杂货商品

2 个答案: