我的 Java 程序似乎在执行期间的某个时间点卡住了（？）。我很困惑。

Question

所以，我正在尝试为我的方法创建一个驱动程序。我提前道歉，我对我在说什么知之甚少。该程序所做的是，它通过泰勒级数为用户输入的数字计算正弦、余弦和指数函数。不允许使用 Math.pow 和 Math.fact。我的编译器没有给我任何错误，我现在完全没有想法。此外，在我按下回车后，扫描仪似乎并没有停止接受输入。它继续接受数字，但不做任何其他事情。当我输入一个字母时，它给出了一个例外。 ID10T 错误的可能性很大。我知道输出的格式还不是很好，但那是因为我还没有机会看到它。如果有人可以帮助我解决这个问题，我将非常感激。提前致谢！

-一个有抱负的代码猴子

驱动程序（Lab4.java）

/*
  This program is being created to solve Lab 4.
*/
import java.util.*;
public class Lab4
{
  public static void main(String[] args)
  {
    String again, more = "y";

    while (more.toUpperCase().charAt(0) == 'Y')
    {
     Scanner keyboard = new Scanner (System.in);
      System.out.println("Input X: ");

         Function number = new Function();
           double x = number.x();
           System.out.println("x = " + x);

         Function sine = new Function();         
            double mySin = sine.funcSine();

         Function cosine = new Function();
            double myCos = cosine.funcCos();

         Function expo = new Function();      
            double myExp = expo.funcExp();   

     System.out.println("\t\t\t\tLibraryResult       My Result");
     System.out.println("\n\t\tsin("  + Function.x() + ")" + " = " + "\t\t\t" + Math.sin(Function.x()) + "\t" + mySin);  
     System.out.println("\n\t\tcos("  + Function.x() + ")" + " = " + "\t\t\t" + Math.cos(Function.x()) + "\t" + myCos); 
     System.out.println("\n\t\texp("  + Function.x() + ")" + " = " + "\t\t\t" + Math.exp(Function.x()) + "\t" + myExp);
     System.out.println("\n\t\t\tDo more (Y/N) ? ");
     more = keyboard.next();
     String junk = keyboard.nextLine();
    }
  }
}

方法（Function.java）

/*
  This class provides the information for the parent to use in order to solve Lab 4.
*/


import java.util.*;
public class Function
{

    Scanner keyboard = new Scanner(System.in);
       public static int number;
       private double temp = 1;
       private double last = 1;


    public static double x()
    {
      Scanner keyboard = new Scanner(System.in);
      double x = keyboard.nextDouble();
      return x;
    }  

    public static double pow(double value, double power)
    {
       if(power == 0)
       {
          return 1;
       }
         double result = value;
         for(int i = 0; i < power -1; i++)
       {
          result = result * value; 
       }
       return result;
    }

    public static double getFact()
    {
       while (number < 0)
       {
           number =(number * -1);
       } 
       double factorial = 1;
       if (0 == (number % 1))
       {
          do
          {
             factorial = factorial * number;
             --number;

          } while (number >= 1);

       }
       else     //Stirling's Approximation
        {
           double e = 2.718281828459;
           double part1 = Math.sqrt(2 * 3.141592653589 * number);
           double part2a = (number / e);
           double part2b = (pow(part2a,number));
           factorial = (part1 * part2b);
        }
            return factorial;
    }

    public static double funcSine()
    {
        int place = 0;  
        double next = x()*1;
        for(number = 3; number <= 30; number = number + 2)
        {                    
           next = next + ((pow((-1),place))*((pow(x(),number))/(getFact())));
           place = place + 1;
        }
        double mySin = next * 1;
        return mySin;
    }

    public static double funcCos()
    {
      int place = 0;
      double next = 1;
      for(number = 2; number <= 30; number = number + 2)
      {
         next = next + ((pow(-1,place))*((pow(x(),number))/(getFact())));
         place = place + 1;
      }
      double myCos = next * 1;
      return myCos;
    }
    public static double funcExp()
    {
       int place = 0;
       double next = 1 + x();
       for(number = 1; number <= 30; number++)
       {
          next = next + ((pow(-1,place))*((pow(x(),number))/(getFact())));
          place = place + 1; 
       }
       double myExp = next * 1;
       return myExp;
    }
}

Answer 1

检查 while 循环的语法：

 while (more.toUpperCase().charAt(0) == 'Y')

想想程序什么时候会不满足这个表达式。

您的代码中还有多个扫描器。它不清楚为什么您需要一遍又一遍地阅读。