如何添加選項讓用戶在使用后重復這個 Java 程序？

Question

我整個晚上都在參加這個節目，我只需要添加一件事，但我正在摸索如何去做。 我 go 如何在用戶已經完成一次程序后添加重復該程序的選項？ 我有一個選項供用戶輸入他們是否想首先使用它，Y 運行程序，然后 N 結束它。 如果用戶已經運行過它，我只需要一些幫助將程序返回到 go 回到最開始，或者如果他們只想退出則再次退出。 謝謝你。 很抱歉我的代碼不是最漂亮的。 我是一個初學者。

import java.util.Scanner;

public class BarChart 

{
    public static void main(String[] args)

    {
        int store1, store2, store3, store4, store5;
        String answer;

        Scanner keyboard = new Scanner(System.in);

        System.out.println("This program will display a bar chart " + 
        " comprised of astericks based on five different stores' " +
        "sales today. 1 asterick = $100 in sales.");

        System.out.println("Would you like to use the program? "
        + "type 'Y' for yes or 'N' to exit the program.");
        answer = keyboard.nextLine();

        if(answer.equalsIgnoreCase("Y"))
        {
            System.out.print("Enter today's sales for store 1: ");
            store1 = keyboard.nextInt();
            while(store1 < 0)
            {
                System.out.println("Error! Sales cannot be less than 0.");
                System.out.print("Enter today's sales for store 1: ");
                store1 = keyboard.nextInt();
            }

            System.out.print("Enter today's sales for store 2: ");
            store2 = keyboard.nextInt();
            while(store2 < 0)
            {
                System.out.println("Error! Sales cannot be less than 0.");
                System.out.print("Enter today's sales for store 2: ");
                store2 = keyboard.nextInt();
            }

            System.out.print("Enter today's sales for store 3: ");
            store3 = keyboard.nextInt();
            while(store3 < 0)
            {
                System.out.println("Error! Sales cannot be less than 0.");
                System.out.print("Enter today's sales for store 3: ");
                store3 = keyboard.nextInt();
            }

            System.out.print("Enter today's sales for store 4: ");
            store4 = keyboard.nextInt();
            while(store4 < 0)
            {
                System.out.println("Error! Sales cannot be less than 0.");
                System.out.print("Enter today's sales for store 4: ");
                store4 = keyboard.nextInt();
            }

            System.out.print("Enter today's sales for store 5: ");
            store5 = keyboard.nextInt();
            while(store5 < 0)
            {
                System.out.println("Error! Sales cannot be less than 0.");
                System.out.print("Enter today's sales for store 5: ");
                store5 = keyboard.nextInt();
            }

            System.out.println("Sales \t Bar Chart");
            System.out.println("----- \t --------------------------");

            System.out.print("Store 1: ");        
            for (int num = 0; num < store1; num += 100)
            {
                System.out.print("*");
            }

            System.out.print("\nStore 2: ");
            for (int num = 0; num < store2; num += 100)
            {
                System.out.print("*");
            }

            System.out.print("\nStore 3: ");
            for (int num = 0; num < store3; num += 100)
            {
                System.out.print("*");
            }

            System.out.print("\nStore 4: ");
            for (int num = 0; num < store4; num += 100)
            {
                System.out.print("*");
            }

            System.out.print("\nStore 5: ");
            for (int num = 0; num < store5; num += 100)
            {
                System.out.print("*");
            }
        }
        
        if(answer.equalsIgnoreCase("N"))
        System.out.print("Program terminated. Have a nice day!");

    }
    
}

我試過重新定向循環，但這只會破壞我的程序。

Answer 1

您目前擁有：

System.out.println("Would you like to use the program? "
    + "type 'Y' for yes or 'N' to exit the program.");
    answer = keyboard.nextLine();

    if(answer.equalsIgnoreCase("Y")) {

// "the program"

    }
    if(answer.equalsIgnoreCase("N"))
    System.out.print("Program terminated. Have a nice day!");

將其更改為：

while (true) {

    // "the program"

    System.out.println("Would you like to use the program again? "
    + "type 'Y' for yes or anything else to exit the program.");
    answer = keyboard.nextLine();

    if (!answer.equalsIgnoreCase("Y")) {
        System.out.print("Program terminated. Have a nice day!");
        break;
    }
}

while(true)永遠循環直到執行break 。

Answer 2

當啟動程序的答案為“是”時，您應該使用循環遍歷代碼。 如果答案是否定的，我們應該跳出循環。 這是一個工作代碼：

 public static void main(String[] args) {
    int store1, store2, store3, store4, store5;
    String answer;

    Scanner keyboard = new Scanner(System.in);

    System.out.println("This program will display a bar chart " +
            " comprised of astericks based on five different stores' " +
            "sales today. 1 asterick = $100 in sales.");

    System.out.println("Would you like to use the program? "
            + "type 'Y' for yes or 'N' to exit the program.");
    answer = keyboard.nextLine();

    while (answer.equalsIgnoreCase("Y")) {
        System.out.print("Enter today's sales for store 1: ");
        store1 = keyboard.nextInt();
        while (store1 < 0) {
            System.out.println("Error! Sales cannot be less than 0.");
            System.out.print("Enter today's sales for store 1: ");
            store1 = keyboard.nextInt();
        }

        System.out.print("Enter today's sales for store 2: ");
        store2 = keyboard.nextInt();
        while (store2 < 0) {
            System.out.println("Error! Sales cannot be less than 0.");
            System.out.print("Enter today's sales for store 2: ");
            store2 = keyboard.nextInt();
        }

        System.out.print("Enter today's sales for store 3: ");
        store3 = keyboard.nextInt();
        while (store3 < 0) {
            System.out.println("Error! Sales cannot be less than 0.");
            System.out.print("Enter today's sales for store 3: ");
            store3 = keyboard.nextInt();
        }

        System.out.print("Enter today's sales for store 4: ");
        store4 = keyboard.nextInt();
        while (store4 < 0) {
            System.out.println("Error! Sales cannot be less than 0.");
            System.out.print("Enter today's sales for store 4: ");
            store4 = keyboard.nextInt();
        }

        System.out.print("Enter today's sales for store 5: ");
        store5 = keyboard.nextInt();
        while (store5 < 0) {
            System.out.println("Error! Sales cannot be less than 0.");
            System.out.print("Enter today's sales for store 5: ");
            store5 = keyboard.nextInt();
        }

        System.out.println("Sales \t Bar Chart");
        System.out.println("----- \t --------------------------");

        System.out.print("Store 1: ");
        for (int num = 0; num < store1; num += 100) {
            System.out.print("*");
        }

        System.out.print("\nStore 2: ");
        for (int num = 0; num < store2; num += 100) {
            System.out.print("*");
        }

        System.out.print("\nStore 3: ");
        for (int num = 0; num < store3; num += 100) {
            System.out.print("*");
        }

        System.out.print("\nStore 4: ");
        for (int num = 0; num < store4; num += 100) {
            System.out.print("*");
        }

        System.out.print("\nStore 5: ");
        for (int num = 0; num < store5; num += 100) {
            System.out.print("*");
        }

        keyboard.nextLine();
        System.out.println("");
        System.out.println("Would you like to reuse the program? "
                + "type 'Y' for yes or 'N' to exit the program.");
        answer = keyboard.nextLine();
    }


    if (answer.equalsIgnoreCase("N"))
        System.out.print("Program terminated. Have a nice day!");

}