尽管已声明变量，但找不到符号-变量 [英] Cannot find Symbol - Variable, despite the variable being declared

问题描述

numThrows变量引发在主方法中使用时找不到的变量错误.即使我在其中一种方法中声明了它. 我在void提示方法中使用了声明变量.该程序旨在使用随机坐标计算Pi，然后使用公式来估算用户给定尝试次数下的饼图.

The numThrows Variable is inciting an error of variable not found when used in the main method. even though i declare it in one of the methods. I use the declare the variable in the void prompt method. This program is designed to calculate Pi using random coordinates then uses a formula to estimate pie over a user given amount of tries.

import java.util.Random;
import java.util.Scanner;
import java.io.PrintWriter;
import java.io.File;
import java.io.IOException;
public class Darts




 public static void prompt()
 {
     Scanner in = new Scanner(System.in);
    System.out.println("How many throws per trial would you like to do?: ");
    int numThrows = in.nextInt();
    System.out.println("How many trials would you like to do?: ");
    int numTrials = in.nextInt(); 



    }


 public static double[] randomX( int numThrows)
 {
     int darts = 0;
     int i = 0;
     double[] cordX = new double[numThrows];
     while(darts <= numThrows)
     {
         cordX[i] = Math.random();
         i++;
        }
     return cordX;
    }
 public static double[]randomY(int numThrows)
 {
     int darts = 0;
     int i = 0;
     double [] cordY = new double[numThrows];
     while(darts <= numThrows)
     {
         cordY[i] = Math.random();
         i++;
        }
     return cordY;


    }
 public static void getHits(int numThrows, double[] cordX, double[] cordY)
 {
     int ii = 0;
     int i = 0;
     double hits = 0;
     double misses = 0;
     for(i = 0; i <= numThrows; i++)
      {
     if( Math.pow(cordX[ii],2) + Math.pow(cordY[ii],2) <= 1)
     {
         hits++;
         ii++;

        }
        else{
            misses++;
        }
    }

    }
 public static double calcPi(int misses, int hits)
{
    int total = hits + misses;
    double pi = 4 * (hits / total);

}
// public static void print(double pi, int numThrows)
// {

   //  System.out.printf("  %-7s         %3.1f            %7s\n", "Trial[//numtrial]: pi = "

 //   }


   public static void main(String[] args)throws IOException
    {
     prompt();
     double[] cordX = randomX(numThrows);
     double[] cordY = randomY(numThrows);
     gethits();
     double pi = calcPi(misses, hits);

}

}

推荐答案

numThrows是提示方法的实例变量.如果您想做我想做的事，请使numThrows在任何方法之外成为一个静态变量.

numThrows is an instance variable to your prompt method. If you want to do what I think you want to do, make numThrows a static variable outside any methods.

它看起来像这样:

public class Darts {
    public static int numThrows
    public static int numTrials

可以从任何方法中引用这些变量.这应该可以解决.

These variables can be referenced from any method. This should fix it.

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