java - 有人可以帮我处理返回函数吗？

Question

我真的是编码初学者。对于学校，我需要创建一个“在线商店”，用户可以在其中添加、删除、查看订单或结账。我创建了用于添加和删除的返回函数，因为在添加或删除项目后我必须返回更新的“购物车”。问题就在这里。

public static void main(String[] args){
    Scanner key = new Scanner(System.in);
    int arr[] = new int[5]; 
    int task, Item, Add, Remove;

    System.out.println("Welcome to Ye Old Shoppe!\nWe sell items at the lowest price in town!\nDue to prices being so low, we sell only 5 items\nevery day and the items change every day!");
    System.out.println("For today, we are selling:");

    System.out.println("\n1. Add Items\n2. Remove Items\n3. View Order\n4. Checkout");
    System.out.print("> ");
    task = key.nextInt();

    if(task == 1){
        System.out.println("\nWhich item do you want to add?");
        System.out.println("\n1. Premium fidget spinners($25)\n2. Nintendo Switch($295)\n3. Handmade leather wallet($65)\n4. 2 packages of A4 paper($50)\n5. Bluetooth Earbuds($40)");
        System.out.print("> ");
        Item = key.nextInt();
        System.out.println("\nHow many?");
        System.out.print("> ");
        Add = key.nextInt();
        addItems(arr, Item, Add);
    }else if(task == 2){
        System.out.println("\nWhich item do you want to remove?");
        System.out.println("\n1. Premium fidget spinners($25)\n2. Nintendo Switch($295)\n3. Handmade leather wallet($65)\n4. 2 packages of A4 paper($50)\n5. Bluetooth Earbuds($40)");
        System.out.print("> ");
        Item = key.nextInt();
        System.out.println("\nHow many?");
        System.out.print("> ");
        Remove = key.nextInt();
        removeItems(arr, Item, Remove);
    }else if(task == 3){
        viewOrder(arr);
    }
}
public static int[] addItems(int[] cart, int item, int addNum){
    if(item == 1){
        while(item > 0 && item < 6 && addNum > 0 && addNum < 6){
            for(int i = 0; i < addNum; i++){
                cart = ArrayUtils.add(cart,1);
                return cart;
            }
        }
        System.out.println("Invalid chocie");
    }else if(item == 2){
        while(item > 0 && item < 6 && addNum > 0 && addNum < 6){
            for(int i = 0; i < addNum; i++){
                cart = ArrayUtils.add(cart,1);
                return cart;
            }
        }
        System.out.println("Invalid chocie");
    }else if(item == 3){
        while(item > 0 && item < 6 && addNum > 0 && addNum < 6){
            for(int i = 0; i < addNum; i++){
                cart = ArrayUtils.add(cart,1);
                return cart;
            }
        }
        System.out.println("Invalid chocie");
    }else if(item == 4){
        while(item > 0 && item < 6 && addNum > 0 && addNum < 6){
            for(int i = 0; i < addNum; i++){
                cart = ArrayUtils.add(cart,1);
                return cart;
            }
        }
        System.out.println("Invalid chocie");
    }else if(item == 5){
        while(item > 0 && item < 6 && addNum > 0 && addNum < 6){
            for(int i = 0; i < addNum; i++){
                cart = ArrayUtils.add(cart,1);
                return cart;
            }
        }
        System.out.println("Invalid chocie");
    }
    return cart;
}

将商品添加到购物车后，我想返回到 main 方法中的主菜单，程序会再次询问我是否要添加、删除、查看订单或结账。我该怎么做？？

Answer 1

要连续获取输入，请使用它。

public static void main(String[] args)
{
    Scanner key = new Scanner(System.in);
    
    while(true)
    {
      String input = scanner. nextLine();//take user input
      if(input.equals("add"))
      {
        int cartUpdated[]=addItems( cart,  item,  addNum);
      }
      else if(input.equals("remove"))
      {
        //call remove method
      }
      else if(input.equals("quit"))
      {
        System.exit(0);//exit(0) : Generally used to indicate   successful termination.
      }
    }
    
}