我无法摆脱“类型 romanCalculator 错误的方法未定义以及非法修饰符是什么问题？

Question

对不起，如果这是一个简单的错误，我对 Java 还是很陌生，并且对所有规则都有问题。我正在尝试创建一个计算器，它接收罗马数字，将它们转换为整数，它们对它们执行操作，然后通过调用方法将它们转换回罗马数字以打印。我把这些放在一起看一些例子，除了 convertFromRoman 方法之外，它似乎几乎都解决了。如果有人看到任何其他错误，请告诉我，因为我真的感到迷茫。代码如下：

package roman_calculator;

import java.util.Scanner;

public class RomanCalculator {
    public static Scanner kbInput = new Scanner(System.in);

    public static String doMath(char operator, int firstNum, int secondNum) {
        switch (operator) {
        case '+':
           return convertToRoman(firstNum + secondNum);
        case '-':
           return convertToRoman(firstNum - secondNum);
        case '*':
           return convertToRoman(firstNum * secondNum);
        case '/':
           return convertToRoman(firstNum / secondNum);
           
        }
        
        return "omething";
        
        /*
         * This method will perform the arithmetic
         * indicated by the operator (+ -* /),
         * invoke convertToRoman to convert answer to Roman number,
         * then return answer
         * */
    }

    public static char getOperator() {
        System.out.println("please choose an operator: +, - , * , or /");
        return kbInput.next().charAt(0);
    }

    public static int getOperands(int which) {
        while (true) {
            System.out.print("Enter operand" + ": ");
            String roman = kbInput.nextLine().toUpperCase();
            int romanNum = convertFromRoman(roman);
            if (romanNum >= 0)
             return romanNum;
            else
             System.out.println("Bad operand, please try again");
        
        
        /*This routine should prompt the user to enter Roman number. 
      convertFromRoman needs to be invoked to convert the Roman number to an integer.
      If the input is invalid (-1 returned from convertFromRoman)
      then complain and prompt the user again. 
    */ 
    }
    public static int convertFromRoman(String roman) {
        
               int result = 0;

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

                int s1 = num(roman.charAt(i));

                if (s1 < 0) {
                 System.out.println("Invalid operand");
                 
                }
                if (i + 1 < roman.length()) {
                 int s2 = num(roman.charAt(i + 1));
                 if (s2 < 0) {
                  System.out.println("Invalid operand");
                  
                 }

                 if (s1 >= s2) {
                  result = result + s1;
                 } else {
                  result = result + s2 - s1;
                  i++;
                 }
                } else {
                 result = result + s1;
                 i++;
                }
               }

               return result;
            
            }
        /*
         * This method will convert Roman number to integer
         * return -1 when input is invalid
         * 
         * */
    }
    public static String convertToRoman(int num) {
        System.out.println(num);
        String roman = "";
        while (num > 0) {
           while (num >= 1000) {
            roman = roman + "M";
            num -= 1000;
           }
           while (num >= 500) {
            roman = roman + "M";
            num -= 500;
           }
           while (num >= 100) {
            roman = roman + "D";
            num -= 100;
           }
           while (num >= 50) {
            roman = roman + "C";
            num -= 50;
           }
           while (num >= 10) {
            roman = roman + "X";
            num -= 10;
           }
           while (num >= 5) {
            roman = roman + "V";
            num -= 5;
           }
           while (num >= 1) {
            roman = roman + "I";
            num -= 1;
           }
        }
        return roman;
        }

        static int num (char r) {
        if (r == 'I')
           return 1;
        if (r == 'V')
           return 5;
        if (r == 'X')
           return 10;
        if (r == 'L')
           return 50;
        if (r == 'C')
           return 100;
        if (r == 'D')
           return 500;
        if (r == 'M')
           return 1000;
        return -1;
        
        /*
         * This method will convert integer to Roman number
         * */
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String result;
        do {

            result = doMath(getOperator(), getOperands(), getOperands());

            System.out.println(result);
            System.out.println("do you want to continue? y/n");
            kbInput.nextLine();
        } while (kbInput.nextLine().charAt(0) == 'y');
        System.out.println("Have a nice day!");
    }

}

Answer 1

您在以下代码中缺少}，最后一个} 丢失。

public static int getOperands(int which) {
    while (true) {
        System.out.print("Enter operand" + ": ");
        String roman = kbInput.nextLine().toUpperCase();
        int romanNum = convertFromRoman(roman);
        if (romanNum >= 0)
         return romanNum;
        else
         System.out.println("Bad operand, please try again");
    }
}

您需要从方法convertFromRoman 中删除最后一个}。

在result = doMath(getOperator(), getOperands(), getOperands()); 行中也有一个错误，您需要将参数传递给getOperands() 或将方法签名更改为getOperator() 或您正在尝试的任何内容。

给您的提示：格式化您的代码可以更容易地阅读和查看层（例如，对于 Eclispe IDE 是 Ctrl + Shift + F）