Problem mit der "While" -Schleife zum Füllen Array mit Binär

Question

Es ist mein erstes Mal hier posten. Ich bin seit vielen Stunden auf dieses Programm gestoßen. Ich habe das Internet durchforstet und fand nur kleine Teile des Codes, die mir mehr Einblick gaben, aber ich bin verwirrt. Es soll binär sein.

Das Programm läuft, aber scheint nur 3 ganze Zahlen in der "umgekehrten" Binärdatei zurückzugeben, wobei die vierte oder mehr immer "0" ist, was anzeigt, dass das Feld leer ist. Jeder weiß was los ist?

/** 
* A program that prints the binary digits of a positive integer 
* 
* @author Your Name 
* @version Today's Date 
*/ 
import java.util.Scanner; 

public class PrintBinaryFixed { 
    public static void main(String[] args) { 

     final int MIN = 0; 
     final int MAX = (int) (Math.pow(2, 30) - 1); 
     int[] digits = new int[30]; // array to hold the digits 

     int number = readInput("Enter an integer from " + MIN + " to " + MAX, MIN, MAX); // number to divide 


     // Your code goes here. This code must do the following: 
     // Declare a "companion" variable to count how many digits stored 
     // Initialize that variable appropriately 
     // While number > 0 
     // Store the remainder (number % 2) in the array 
     // Update the companion variable 
     // Set number to be number/2 
     // Display the filled portion of the array in reverse order 
     // System.out.println(number); 
     int index = 0; // the counter 
     int q = number/2; // quotient 
     int r = number % 2; // remainder 
     int n = 1; // iteration 
     int qr = 0; // returning quotient 


     while (number > 0) { 

      number = (int) q; 
      // System.out.println(number); 
      // System.out.println("Quotient - "+q); 
      System.out.println("Remainder - " + r); 
      // System.out.println("Iteration - "+n); 

      qr = (int) q/2; // Quotient to be returned 
      r = (int) q % 2; // New Remainder to be returned 
      q = qr; // Resetting the number to be divided 
      // n++; // Incrementing the loop 

      digits[index] = r; 
      index++; 

     } 

     listBackwardsFrom(digits, index); 
    } 

    /** 
    * Print the contents of an array backwards, starting from index last 
    * 
    * @param array: 
    *   an array of integers 
    * @param last: 
    *   the index of the starting location 
    */ 
    public static void listBackwardsFrom(int[] array, int last) { 
     for (int i = 0; i < last; i++) { 
      //System.out.println(i); 
      System.out.println(array[i]); 
      //System.out.println(array[28]); 
      //System.out.println(array[27]); 
      //System.out.println(array[26]); 
     } 
    } 

    /** 
    * Read in an integer between two given bounds 
    * 
    * @param prompt: 
    *   the prompt to show the user 
    * @param min: 
    *   the smallest acceptable input value 
    * @param max: 
    *   the largest acceptable input value 
    */ 
    public static int readInput(String prompt, int min, int max) { 
     Scanner scan = new Scanner(System.in); 
     boolean check = true; 
     System.out.println(prompt); 
     String userinput = scan.next(); 
     while (check) { 

      try { 

       if (Integer.valueOf(userinput) <= max && Integer.valueOf(userinput) >= min) { 
        check = false; 
       } else { 
        check = true; 
        System.out.println("enter an integer in valid range"); 
        userinput = scan.next(); 

       } 
      } catch (NumberFormatException e) { 
       check = true; 
       System.out.println("enter a valid integer"); 
       userinput = scan.next(); 
      } 

     } 

     return Integer.parseInt(userinput); 

    } 

    /** 
    * Read in a positive integer and return its value 
    * 
    * @param the 
    *   prompt to be shown to the user 
    */ 
    public static int readInteger(String prompt) { 
     Scanner scan = new Scanner(System.in); 
     boolean check = true; 
     System.out.println(prompt); 
     String userinput = scan.next(); 
     while (check) { 

      try { 

       if (Integer.valueOf(userinput) > 0) { 
        check = false; 
       } else { 
        check = true; 
        System.out.println("enter a valid integer"); 
        userinput = scan.next(); 

       } 
      } catch (NumberFormatException e) { 
       check = true; 
       System.out.println("enter a valid integer"); 
       userinput = scan.next(); 
      } 

     } 

     return Integer.parseInt(userinput); 
    } 
} 

Answer 1

Überprüfen Sie dies, speichern Sie die Erinnerung, bevor Sie den nächsten Zyklus berechnen.

 while (number > 0) { 
     number = (int) q; 
     System.out.println("Remainder - " + r); 
     digits[index] = r; 
     qr = (int) q/2; // Quotient to be returned 
     r = (int) q % 2; // New Remainder to be returned 
     q = qr; // Resetting the number to be divided 
     index++; 
    } 

und vom Ende bis zum Anfang durchlaufen.

public static void listBackwardsFrom(int[] array, int last) { 
    for (int i = last-1; i >= 0; i--) { 
     System.out.print(array[i]); 
    } 
}