跨函数连接字符串

Question

我正在开发一个程序，该程序将获取一个文本文件，并将数字从0-99转换为文字（即0）-

static ArrayList<String> list;

    static void convertToWord(char[] num, String fullString)
    {
        //number to word : https://www.geeksforgeeks.org/convert-number-to-words/
        String[] single_digits = new String[]{ "zero", "one",
                "two", "three", "four",
                "five", "six", "seven",
                "eight", "nine"};
        String[] two_digits = new String[]{"", "ten", "eleven", "twelve",
                "thirteen", "fourteen",
                "fifteen", "sixteen", "seventeen",
                "eighteen", "nineteen"};
        String[] tens_multiple = new String[]{"", "", "twenty", "thirty", "forty",
                "fifty","sixty", "seventy",
                "eighty", "ninety"};

        int len = num.length;

        if (len == 0)
        {
            System.out.println("Error");
            return;
        }

        if (len == 1)
        {
            fullString += single_digits[num[0] - '0'];
            return;
        }

        if (len > 2)
        {
            System.out.println("No numbers greater than 99");
            return;
        }

        int x = 0;
        while (x < num.length)
        {
                if (num[x] - '0' == 1)
                {
                    int sum = num[x] - '0' +
                            num[x] - '0';
                    fullString += two_digits[sum];
                    return;
                }

                else if (num[x] - '0' == 2 &&
                        num[x + 1] - '0' == 0)
                {
                    fullString += "twenty";
                    return;
                }

                else
                {
                    int i = (num[x] - '0');
                    if(i > 0)
                        fullString += tens_multiple[i]+" ";
                    else
                        fullString += "";
                    ++x;
                    if (num[x] - '0' != 0)
                        fullString += single_digits[num[x] - '0'];
                }
            ++x;
        }
    System.out.println(fullString);
    }

    public static void main(String[] args) throws FileNotFoundException
    {
        /* read each element of file as a separate member of array:
        https://stackoverflow.com/questions/28643680/java-storing-each-word-from-an-input-file-in-an-array-of-strings */
        String fullString = "";
        Scanner s = new Scanner(new File("C:/Users/Zach/Desktop/Fall 2020/Java_Kotlin/java-kotlin-zpheesaker/KattisNumberstoWords/app/input.txt"));
        list = new ArrayList<String>();
        while(s.hasNext())
        {
            String token = s.next ();
            list.add(token);
        }

        for (int i = 0; i < list.size(); i++)
        {
            // check if number by regex: https://stackoverflow.com/questions/18590901/check-if-a-string-contains-numbers-java
            if(list.get(i).matches(".*\\d.*"))
            {
                convertToWord(list.get(i).toCharArray(), fullString);
            }
            else {
                fullString += (list.get(i) + " ");
            }
        }
        System.out.println(fullString);
    }
}

这里有几行输出（每一行都是不同的system.out行）：

-Piqued favour twenty three
-Piqued favour stairs it enable exeter as seeing. Remainder met improving but forty one
-Piqued favour stairs it enable exeter as seeing. Remainder met improving but engrossed sincerity age. Better but seventy eight

这是输入文件上的三行：

Piqued favour 23 stairs it enable exeter as seeing.
Remainder met improving but 41 engrossed sincerity age.
Better but 78 length denied abroad are.

如您所见，数字随系统一起添加和打印。从函数convertToWord中退出，但一旦返回main，就会丢失。如何跨函数将这些转换附加到字符串？

Answer 1

我可以想出两种方法：

如果您想将fullString的值返回给您的main方法，我建议您修改转换ToWord使其具有返回类型String，如下所示：

static void convertToWord(char[] num, String fullString)

然后，该方法需要返回fullString而不是什么都不返回。

最后，将main方法中的返回值或convertToWord赋给一个变量，您可以在main中使用它。

或者，您可以将fullString声明为StringBuffer，并使用方法append（）对其进行追加。