程序的功能是从两个独立的文本文件中读取，一个文本文件称为礼品（随机名称）和成本（每天的总成本）。我必须打印如果用户输入是3，它将打印与这3天的费用3行。另外，我还要打印12天的总费用。
我的代码

import java.io.File;

import java.io.FileNotFoundException;

import java.util.Scanner;

import java.text.NumberFormat;

public class GiftsTwelveDays{

    public static void main(String[] args) {

        String[] gifts = new String[12];

        double[] costGifts = new double[12];

        String total = new String();

        //Following code reads the Gifts.txt file

        File file = new File("gifts.txt");

        try 
        {
            Scanner scannerFile = new Scanner(file);

            while (scannerFile.hasNextLine()) 

            {
                int i = scannerFile.nextInt();

                String present = scannerFile.nextLine();

                gifts[i - 1] = present;

            }

            scannerFile.close();

        }

        catch (FileNotFoundException e) 

        {
            System.out.println("File not Found.");
        }

        //This reads the cost and stores in array of double

        File file1 = new File("cost.txt");

        try 
        {
            Scanner scannerFile = new Scanner(file1);

            while (scannerFile.hasNextInt()) {

                scannerFile.next();

                if(scannerFile.hasNextInt())

                {

                    int i = scannerFile.nextInt();

                    double cost = scannerFile.nextDouble();

                    costGifts[i-1] = cost;

                }

                else
                {

                    scannerFile.nextInt();

                    total = scannerFile.nextLine();

                }

            }

            scannerFile.close();

        }

        catch (FileNotFoundException e) 
        {

            System.out.println("File could not be found");;

        }

        //following gets user input and runs

        Scanner userInput = new Scanner(System.in);

        NumberFormat money = NumberFormat.getInstance(); //for format with comma

        money.setGroupingUsed(true);

        double costDay = 0;

        System.out.println("Enter the day:");

        int choice = userInput.nextInt();

        userInput.nextLine();

        if (choice < 1 || choice > 12)//runs if choice is invalid

        {

            System.out.println("Invalid Choice");

        }

        else

        {

            System.out.println("Your gifts for the day " + choice + " are: \n");

            //calculates the day cost and prints gift simultaneously

            for(int i = 0; i < choice; i++)

            {

                System.out.println((i + 1) + gifts[i]);

                costDay = costDay + costGifts[i];

            }

            //prints the calculated cost.

            System.out.println("\nCost of Day: $" + money.format(costDay));

            System.out.println("\nTotal Cost for Twelve Days: $" + total);

        }

    }

}

输出：

Enter the day:
3
Your gifts for the day 3 are: 

1 Patridge in a Pear Tree
2 Turtle Doves
3 French Hen

Cost of Day: $0

Total Cost for Twelve Days: $

礼品.txt

1 Patridge in a Pear Tree
2 Turtle Doves
3 French Hen
4 Calling Birds
5 Gold Rings
6 Geese-a-Laying
7 Swans-a-Swimming
8 Maids-a-Milking
9 Ladies Dancing
10 Lords-a-Leaping
11 Piper
12 Drummers Drumming

成本.txt

220.13
595.13
776.63
1376.59
2126.59
2516.59
15641.59
15699.59
23252.43
33252.43
36056.83
39094.93