Java

Question

我对使用 java 还很陌生，所以可能没有必要给这个页面评分（除非你真的想要，我不在乎），所以我只是一个学生并且我不喜欢编程。

我正在查看这里的起始代码页，但我对应该使用什么方法来计算素数感到困惑。我的 Java 包包含 3 个编码页； 3 是 Mymain (dllmain)、Mylist(dlllist) 和 Mynode(dllnode)。

我知道我至少需要输入一种方法来计算素数。

接下来，我将向您展示 Mymain 脚本和 Mylist 中的两个质数方法以及一个 Mynode 构造函数，以防您需要查看此代码的工作原理。

谢谢。

package sample3;
import java.io.*;
public class Mymain {
 
 public static void main(String[] args) {
  
  // Declaring variables for "Mynode"
  Mynode D1 = null; //"D" stands for Data
  Mynode D2 = null;
  Mynode D3 = null;
  
  // Declaring variables for "Mylist"
  Mylist L1 = new Mylist(); //The "L" stands for List.
  Mylist L2 = new Mylist(); 
  Mylist L3 = new Mylist();
  
  /* Using the buffered reader to scan the following txt files.
  *
  * f1.txt // The "f" stands for file.
  * f2.txt
  * f3.txt
  * 
  */
  String read = "";
  BufferedReader br = null; //Buffered reader as scanner.
  
   try {br = new BufferedReader(new FileReader("f1.txt"));
     while ((read = br.readLine()) != null) {
     Mynode Data = new Mynode(Integer.parseInt(read));
     D1 = Data;
     L1.addStart(Data);}     
        br.close(); //close file
         
     br = new BufferedReader(new FileReader("f2.txt"));
     while ((read = br.readLine()) != null) {
     Mynode Data = new Mynode(Integer.parseInt(read));
     D2 = Data;
     L2.addStart(Data);}     
        br.close(); //close file
    
     br = new BufferedReader(new FileReader("f3.txt"));
     while ((read = br.readLine()) != null) {
     Mynode Data = new Mynode(Integer.parseInt(read));
     D3 = Data;
     L3.addStart(Data);}
     br.close(); //close file
     }
   
   /* Error checker:
    * 
    * Checks if the file is valid.
    * Checks the input and output of this package.
    * Checks if all the figures in the file is numeric.
    * 
    */
   catch (FileNotFoundException e)
   {e.getMessage();} 
   catch (IOException e) 
   {e.getMessage();}
   catch (NumberFormatException e) 
   {e.getMessage();}
      
   //Introduction for describing the program when it runs
   System.out.println("Outputting all the following data:\n");
   System.out.println("Displaying node count from each file in order, reversed order \nprime numbers and intersections.");
   System.out.println("This program contains: files - f1.txt, f2.txt, f3.txt \n");
   
   System.out.println("____________________________________________________________\n");
   // Outputting the results from all the lists
   System.out.println("Numbers list 1- \t\tNode count:" + L1.numNodes() + "\n");      //Displaying all the numbers from the first number to the last number.
   L1.printHead(D1);
   System.out.println("\nIn reversed order: ");           //Displaying all the numbers in backwards order from the last number to the first number.
   L1.printBackwards(D1);
   System.out.println("\n------------------------------------------------------------");

   System.out.println("\nNumbers list 2- \t\tNode count:" + L2.numNodes() + "\n");  //Displaying all the numbers from the first number to the last number.
   L2.printHead(D2);
   System.out.println("\nIn reversed order: ");        //Displaying all the numbers in backwards order from the last number to the first number.
   L2.printBackwards(D2);
   System.out.println("\n-------------------------------------------------------------");
   
   System.out.println("\nNumbers list 3- \t\tNode count:"  + L3.numNodes() + "\n"); //Displaying all the numbers from the first number to the last number.
   L3.printHead(D3);
   System.out.println("\nIn reversed order: ");        //Displaying all the numbers in backwards order from the last number to the first number.
   L3.printBackwards(D3);
   System.out.println("\n-------------------------------------------------------------");
   
   System.out.println("\n\nPrime numbers from List1-");         //Displaying all the existing prime numbers.
   L1.printPrime(D1);
   System.out.println("\n\nPrime numbers from List2-");         //Displaying all the existing prime numbers.
   L2.printPrime(D2);
   System.out.println("\n\nPrime numbers from List3-");         //Displaying all the existing prime numbers.
   L3.printPrime(D3);
   
   Mylist Ans1 = Mylist.Intersect(L1, L2);          //Displaying the numbers that intersects from the lists 1,2 and 3.
   Mylist Ans2 = Mylist.Intersect (Ans1, L3);
   System.out.println("\n\nIntersections");
   Ans2.printHead(Ans2.Head);
  }
}

这里应该输出从文件中提取的素数的两个素数代码。

第一个是素数计数器，我不确定如何更改它以使其正常工作。
第二种方法有效，程序为运行.
时可以输出显示所有素数
第一个适用于数组 txt 文件但不适用于双链表的质数代码。

public static int primeChecker(int[] array) { 
   int PrimeNo = 0;        
  for(int i=0;i<array.length;i++) {         
   if(isPrime(array[i])) {      
    PrimeNo++;        
    
   }
 } 
 return PrimeNo;          
}

和第二个。

//Print Primes
public void printPrime(Mynode p) {
    int k = 0;
    while (p != null) 
    {
        int x = p.Data;
        if (isPrime(x)) 
        {
            k++;
            System.out.print(p.Data + "\t");
            if (k % 5 == 0) {
                System.out.println("");
                k = 0;
            }
        }
        p = p.Next;
    }

最后是 "Mynode" 代码页。

Mynode {
 public int Data;
 public Mynode Next;
 public Mynode Prev;
 
 public Mynode (int Data) {
  Prev = null;
  this.Data = Data;
  Next = null;

抱歉代码太长。

Answer 1

要为双链表的 Mylist 实现重载 primeChecker 方法，您需要循环遍历链表的每个元素并在每次遇到素数时递增一个变量，就像您对为数组重载了 primeChecker 方法。我不确定您的 Mylist 双链表的确切实现，但它可能看起来像这样。

public static int primeChecker(Mylist list) { 
    int PrimeNo = 0;
    //insert whatever method here gives you the first node of Mylist
    //I inserted start() to demonstrate, that may or may not be right
    Mynode p = list.start();                    
    while (p != null) 
    {
        int x = p.Data;
        if (isPrime(x)) 
        {
            PrimeNo++;
        }
        p = p.Next;
    }
    return PrimeNo;                               
}

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