Discounting program

[civicjai]

Can anyone teach me how to wirte this
Many Thanks

Supermarkets sometimes have discounts on multiple purchases. For example, the unitprice for “mango” is $1.89, but buying two of the product will cost $2.50. The discount information is stored with each item in the items array.

For those items that offer a discount for multiple purchases, the discounted price is shown when it applies.

An example is shown below:
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):
==========Bill==========
mango/$1.89
mango/discounted (2@2.5) $0.61
mango/$1.89
mango/discounted (2@2.5) $0.61
Amount due: $5
Thanks for shopping with us!


--------------------------------------------------------------------------------
For the code i write so far the Bill i only can print the bill like this

Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):
==========Bill==========
mango/$1.89
mango/$1.89
mango/$1.89
mango/$1.89
Amount due: $5
Thanks for shopping with us!

Please Help me. And please give me more detail, cause this is my first year to learn java, i want to learn more and make me more understand~ A lot of thanks

.CheckoutProgram.java.
 
import java.io.*;
import java.text.DecimalFormat;
 
public class CheckoutProgram {
 
    public void start() {
 
        SalesItem[] items = getStock();
 
        System.out.print("Type item code (press enter to finish):");
         String wordIn = Keyboard.readInput();
 
         SalesItem[] goods = new SalesItem[1000];
 
        int count = 0;    
         while (wordIn.length()>=4 && wordIn.length()<=4){
         for (int i=0;i<items.length;i++) {
        if (items[i] != null && wordIn.equals(items[i].getItemCode())){
        System.out.println(items[i]);
            goods[count] = items[i];
        }
 
        }
         System.out.print("Type item code (press enter to finish):");
         wordIn = Keyboard.readInput();
        count++;
}         
 
        System.out.println();
        System.out.println("==========Bill==========");
 
        double amountDue = 0.0;
 
        for (int i=0; i<count; i++){
 
                System.out.println(goods[i]);
            amountDue = amountDue + goods[i].getUnitPrice();
    }
 
 
 
 
        System.out.println();
        System.out.println("Amount due: $" + new DecimalFormat().format(amountDue));
        System.out.println("Thanks for shopping with us!");
 
}
 
    // method to read in "stock.txt" and store the items for sale in an array of type SalesItem
    private SalesItem[] getStock(){
        SalesItem[] items = new SalesItem[1000];
        try {
            BufferedReader br = new BufferedReader(new FileReader("stock.txt"));
            String theLine;
            int count = 0;
            while ((theLine = br.readLine()) != null) {
                 String[] parts = theLine.split(",");
                 items[count] = new SalesItem(parts[0],parts[1],Double.parseDouble(parts[2]));
                 if (parts.length==4){
                     String discount = parts[3];
                     String numPurchases = discount.substring(0, discount.indexOf("@"));
                     String price = discount.substring(discount.indexOf("@")+1);
                     items[count].setNumPurchases(Integer.parseInt(numPurchases));
                     items[count].setDiscountedPrice(Double.parseDouble(price));
                 }
                 count++;                 
            }
        } 
        catch (IOException e) {
            System.err.println("Error: " + e);
        }
        return items;
    }    
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
}
 
 
..

..SalesItem.java
 
import java.text.DecimalFormat;
 
public class SalesItem {
    private String itemCode; //the item code
    private String description; // the item description
    private double unitPrice; // the item unit price
 
    // An item may offer a discount for multiple purchases 
    private int numPurchases; //the number of purchases required for receiving the discount
    private double discountedPrice; // the discounted price of multiple purchases
 
    // the constructor of the SalesItem class
    public SalesItem (String itemCode, String description, double unitPrice){
        this.itemCode = itemCode;
        this.description = description;
        this.unitPrice = unitPrice;
    }
 
    // accessor and mutator methods
 
    public String getItemCode(){
        return itemCode;
    }
 
    public void setItemCode(String itemCode){
        this.itemCode = itemCode;
    }
 
    public String getDescription(){
        return description;
    }
 
    public void setDescription(String description){
        this.description = description;
    }
 
    public double getUnitPrice(){
        return unitPrice;
    }
 
    public void setUnitPrice(double unitPrice){
        this.unitPrice = unitPrice;
    }
 
    public int getNumPurchases(){
        return numPurchases;
    }
 
    public void setNumPurchases(int numPurchases){
        this.numPurchases = numPurchases;
    }
 
    public double getDiscountedPrice(){
        return discountedPrice;
    }
 
    public void setDiscountedPrice(double discountedPrice){
        this.discountedPrice = discountedPrice;
    }
 
    // the string representation of a SalesItem object
    public String toString(){
        return description + "/$" + new DecimalFormat().format(unitPrice);
    }
}
 
..

..stock.txt
1000,low-fat milk (1 litre),2.15
1001,good-morning cereal,5.60
1002,mango,1.89,2@2.50
1003,Coca-Cola (300 ml),2.5
..

[dmjpro]

Use code Tags while you do Post.

And point out the specific fragment of Code.

Kind regards,
Dmjpro.

[forse]

I read your question twice and still cannot understand what you want.
Be more precise on what you want..

I can only guess that you are using an ARRAY and you have problems dealing with two dimensional arrays.

If that is the case then you may read a Tutorial on Multidimensional or arrays of arrays in Java

[civicjai]

Part one: simple checkout
The checkout program records purchases. An item code is to be entered by the user. If it
is an existing item code that matches an item in the items array (as given in
CheckoutProgram.java), a description of the item with its unit price is displayed.
For example, if the user types the item code “1000” and then presses the Enter key,
“low-fat milk (1 litre)/$2.15” is displayed on the screen, followed by
another prompt for typing the next item code.
Type item code (press enter to finish):1000
low-fat milk (1 litre)/$2.15
Type item code (press enter to finish):
If the entered item code cannot be matched to an item in the items array, the program
should continue with another prompt for typing an item code. For example, if the user
continues using the program by typing the item code “6666” and then presses the Enter
key, another prompt for typing an item code is shown.
Type item code (press enter to finish):1000
low-fat milk (1 litre)/$2.15
Type item code (press enter to finish):6666
Type item code (press enter to finish):
If the user presses the Enter key at the prompt without first typing an item code, the
program finishes executing by displaying a bill, which lists all the items bought (item
description and unit price), and the total amount due. An example is shown below:
Type item code (press enter to finish):1000
low-fat milk (1 litre)/$2.15
Type item code (press enter to finish):1001
good-morning cereal/$5.6
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1003
Coca-Cola (300 ml)/$2.5
Type item code (press enter to finish):


==========Bill==========
low-fat milk (1 litre)/$2.15
good-morning cereal/$5.6
mango/$1.89
Coca-Cola (300 ml)/$2.5
Amount due: $12.14
Thanks for shopping with us!
Hint:
• To implement this program, you need to store the purchases in an array. The size
of the array should be declared as a big number, say 1000. You also need to use
an integer counter to count the actual number of purchases.
• You MUST break your program into methods. For example, you may have:
- a method to display a purchased item on the screen,
- a method to record the purchased items,
- a method to calculate the amount due.
• Null values in the array need to be handled well so that no
NullPointerExceptions are generated during the execution of the program.
• To format a double variable e.g. amountDue, as money, use
“$" + new DecimalFormat().format(amountDue)
Part two: multiple purchase discounts
Supermarkets sometimes have discounts on multiple purchases. For example, the unit
price for “mango” is $1.89, but buying two of the product will cost $2.50. The
discount information is stored with each item in the items array.
The checkout program displays a bill similar to Part One, but for those items that offer a
discount for multiple purchases, the discounted price is shown when it applies.
An example is shown below:
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):
==========Bill==========
mango/$1.89
mango/discounted (2@2.5) $0.61
mango/$1.89
mango/discounted (2@2.5) $0.61
Amount due: $5
Thanks for shopping with us!

In the above example, four of the “mango” are purchased. The multiple purchase
discount for “mango” (2@2.50) applies to every two “mango” items. So the program
gives every second “mango” a discounted price ($0.61) which makes two purchases
$2.50 (every first “mango” is still priced using its unit price $1.89). Another
example is shown below:
Type item code (press enter to finish):1000
low-fat milk (1 litre)/$2.15
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1001
good-morning cereal/$5.6
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):1003
Coca-Cola (300 ml)/$2.5
Type item code (press enter to finish):1002
mango/$1.89
Type item code (press enter to finish):
==========Bill==========
low-fat milk (1 litre)/$2.15
mango/$1.89
good-morning cereal/$5.6
mango/discounted (2@2.5) $0.61
Coca-Cola (300 ml)/$2.5
mango/$1.89
Amount due: $14.64
Thanks for shopping with us!

To work out whether the price is to be a discounted price, you need to count the
number of previous purchases for items with the same item code.

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i already done the part1 ,but i am not sure i done it correct or not~
but i can't do part 2, i have no idea how to do part2 ~ and i haven't learn two dimensional arrays, so i think i can't use it for this assignment. can i use another way to slove part 2

[JosAH]

Arrays are sooo Fortranesque; Java is a little object oriented language. I know this
is homework, but aren't you allowed to use simple classes? I can imagine a
DiscountInfo class associated with an item; both stored in some sort of Map.
The Map is controlled by a simple DiscountManager you can consult given an
item and the amount of items bought ...

kind regards,

Jos