Question

我需要使用二维数组作为赋值的一部分。

我需要在main方法的开头为行计数器和一个提供10行和4列的矩形字符串数组声明变量
在为每次计算计算，格式化并显示resutls的代码之后，添加将格式化值作为字符串存储在数组的下一行中的代码（您需要使用整数类的toString方法）存储年份值。）

我已经为一个计数器声明了一个10x4的数组和一个变量，但我在添加代码时遇到问题，这些代码将格式化的值存储为数组的下一行中的字符串（您需要使用整数类的toString方法来存储年份值）。

下面是我在下面编写的这个问题（2）的代码，它似乎打印了一个空列表，如何让我的代码打印出来？以下代码在我看来是导致问题的一个是正确的吗？我有点困惑。

    FutureValueArray[counter][0] = Double.toString(monthlyInvestment);
    FutureValueArray[counter][1] = Double.toString(interestRate);
    FutureValueArray[counter][2] = Integer.toString(years);
    FutureValueArray[counter][3] = Double.toString(futureValue);

/*This is how my table should look like.
Inv/Mo. Rate Years Future Value
$100.00 8.0% 10 $18.416.57
$125.00 8.0% 10 $23,020.71*/


public static void main(String[] args)
{
    String[][] FutureValueArray = new String [10][4];
    int counter = 0;
    // display a welcome message
    System.out.println("Welcome to the Future Value Calculator");
    System.out.println();

    // perform 1 or more calculations
    Scanner sc = new Scanner(System.in);
    String choice = "y";
    while (choice.equalsIgnoreCase("y"))
    {

        // get the input from the user
        System.out.println("DATA ENTRY");
        double monthlyInvestment = getDoubleWithinRange(sc,
            "Enter monthly investment: ", 0, 1000);
        double interestRate = getDoubleWithinRange(sc,
            "Enter yearly interest rate: ", 0, 30);
        int years = getIntWithinRange(sc,
            "Enter number of years: ", 0, 100);

        // calculate the future value
        double monthlyInterestRate = interestRate/12/100;
        int months = years * 12;
        double futureValue = calculateFutureValue(
            monthlyInvestment, monthlyInterestRate, months);

        // get the currency and percent formatters
        NumberFormat currency = NumberFormat.getCurrencyInstance();
        NumberFormat percent = NumberFormat.getPercentInstance();
        percent.setMinimumFractionDigits(1);

        // format the result as a single string
        String results =
              "Monthly investment:\t"
                  + currency.format(monthlyInvestment) + "\n"
            + "Yearly interest rate:\t"
                  + percent.format(interestRate/100) + "\n"
            + "Number of years:\t"
                  +  years + "\n"
            + "Future value:\t\t"
                  + currency.format(futureValue) + "\n";

        // print the results
        System.out.println();
        System.out.println("FORMATTED RESULTS");
        System.out.println(results);

        FutureValueArray[counter][0] = Double.toString(monthlyInvestment);
        FutureValueArray[counter][1] = Double.toString(interestRate);
        FutureValueArray[counter][2] = Integer.toString(years);
        FutureValueArray[counter][3] = Double.toString(futureValue);
        for(int i = 0; i < FutureValueArray.length; i++)
        {
            for (int j = 0; j < FutureValueArray[i].length; j++)
                System.out.println(FutureValueArray[i][j] + " ");
            System.out.println("\n");
        }
        // see if the user wants to continue
        System.out.print("Continue? (y/n): ");
        choice = sc.next();
        counter++;
        System.out.println();
    }
}

Answer 1

您的代码似乎没问题。

如果你改变了

for(int i = 0; i < FutureValueArray.length; i++)

要

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

您不会打印尚未设置的FutureValueArray行的空值。

此外，您似乎希望在该循环中使用System.out.print()函数，而不是System.out.println()函数。

添加代码将格式化的值存储为数组的下一行中的字符串？

1 个答案: