如何解决带有OOP的Java应用程序杂货订购逻辑
我正在做杂货订购系统,但订购逻辑有问题。
当前,该程序会询问客户他们要订购多少杂货,但我发现这是一种订购方法,而无需在开始时指定要订购的订购数量。
有人知道吗?谢谢。
下面是驱动程序类Shop.java
package groceries.ordering.system;
import java.util.*;
public class Shop {
public static void main(String[] args){
Scanner myScanner = new Scanner(System.in);
Category[] groceries = {new Category("Apple 1pcs",1.5,"Fruit"),new Category("Orange 1pcs",1.4,new Category("Egg 10pcs",8,"Dairy"),new Category("Full Cream Milk",6.5,new Category("Olive Oil 1L",30,"Cooking Oil"),new Category("Palm Oil 1L",20,"Cooking Oil")};
displayMenu(groceries);
System.out.print("How many groceries you would like to order: ");
int totalGroceries = myScanner.nextInt();
OrderItem[] items = new OrderItem[totalGroceries];
for(int i=0;i<items.length;i++){
System.out.println("Enter your choice of groceries (1 - 6) : ");
int choice = myScanner.nextInt()-1;
System.out.println("Enter quantity ordered: ");
int quantity = myScanner.nextInt();
items[i] = new OrderItem(groceries[choice],quantity);
}
Order order = new Order(items,totalGroceries);
displayOrderItem(items);
System.out.printf("%65s %9.2f\n","Grand Total: ",order.getGrandTotalPrice());
}
public static void displayMenu(Groceries[] groceries){
System.out.printf("\t========================================\n");
System.out.printf("\tWelcome to the Groceries Ordering System\n");
System.out.printf("\t========================================\n");
System.out.printf("%-10s %-25s %-11s %s \n\n","No","Groceries","Price(RM)","Category");
for(Groceries grocery : groceries){
System.out.println(grocery.displayMenu());
}
System.out.println("\n");
}
public static void displayOrderItem(OrderItem[] items){
System.out.printf("\n\t\t\t\t Ordered Item\n");
System.out.printf("\t\t\t\t===============\n");
System.out.printf("%-10s %-20s %-14s %-13s %-13s\n","Quantity","Total Price(RM)");
System.out.printf("--------------------------------------------------------------------------------------\n");
for(OrderItem item : items){
System.out.println(item.displayOrder());
}
System.out.printf("--------------------------------------------------------------------------------------\n");
}
}
这是Groceries类(我认为不会发布任何相关类,因此不会发布该类的子类(类别)
package groceries.ordering.system;
public abstract class Groceries {
private String name;
private double price;
public Groceries() {
this("",0);
}
public Groceries(String prodName,double prodPrice){
super();
name = prodName;
price = prodPrice;
}
public String getName() {
return name;
}
public double getPrice() {
return price;
}
public String displayMenu(){
return String.format("%-25s %-11.2f ",name,price);
}
}
这是OrderItem类
public class OrderItem {
private Groceries groceries;
private int quantity;
private static int prodCount = 1;
public OrderItem(Groceries groceries,int quantity) {
this.groceries = groceries;
this.quantity = quantity;
}
public double getUnitPrice(){
return groceries.getPrice();
}
public double getSubTotalPrice(){
return getUnitPrice() * quantity;
}
public String displayOrder() {
return String.format("%-10d %-20s %9.2f %13d %19.2f",prodCount++,groceries.getName(),getUnitPrice(),quantity,getSubTotalPrice());
}
}
最后是Order类
public class Order {
private OrderItem[] items;
private int totalItem;
public Order(OrderItem[] items,int totalItem) {
this.items = items;
this.totalItem = totalItem;
}
public double getGrandTotalPrice() {
double price = 0.0;
for (OrderItem item : items) {
price += item.getSubTotalPrice();
}
return price;
}
}
解决方法
好的。您可以通过两种方式做到这一点。
- 事先创建一个非常大的数组(不推荐)。
- 使用一些
List
(ArrayList
或LinkedList
等),并继续添加项目,直到完成用户操作。
List<OrderItem> items = new ArrayList<>();
do {
System.out.println("Enter your choice of groceries (1 - 6) : ");
int choice = myScanner.nextInt()-1;
System.out.println("Enter quantity ordered: ");
int quantity = myScanner.nextInt();
items.add(new OrderItem(groceries[choice],quantity));
// compute shouldContinue - something like asking the user to enter -1 to quit.
} while(shouldContinue);
,
是,在数组下方的位置使用ArrayList
或LinkedList
的List实现并使用其功能:
替换此项-OrderItem[] items = new OrderItem[totalGroceries];
with ArrayList- List<OrderItem> items = new ArrayList<>();
如果要在多线程环境中运行此应用程序,也可以使用CopyOnWriteArrayList
。
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