程序每次都應該是隨機的時候會給出相同的結果

Question

這個程序的目標是對一個分數取2個隨機變量，看看它們是否已經減少了。假設的可能性是6 /（pi^2）。我運行了1000個不同的變量組合，並確定有多少個並沒有減少。然後我解決pi。

但是每次運行它時，輸出結果都是「pi 2.449489742783178」。

任何人都知道爲什麼？謝謝。

import java.util.*; 

public class ratio1 { 

    /** 
    * @param args 
    */ 
    public static void main(String[] args) { 
     // TODO Auto-generated method stub 
     int nonReducedCount = 0; //counts how many non reduced ratios there are 
     for(int i =1; i<=1000; i++){ 

      Random rand = new Random(); 
      int n = rand.nextInt(1000)+1; //random int creation 
      int m = rand.nextInt(1000)+1; 
      //Ratio ratio = new Ratio(n,m); 
      if (gcd(n,m)> 1){ // if the ratio was not already fully reduced 
       nonReducedCount++; // increase the count of non reduced ratios 
      } 
     } 

     int reducedCount = 1000 - nonReducedCount; //number of times the ratio was reduced already 
     double reducedRatio = reducedCount/nonReducedCount; //the ratio for reduced and not reduced 
     reducedRatio *= 6; 
     reducedRatio = Math.sqrt(reducedRatio); 
     System.out.println("pi is " + reducedRatio); 
    } 

    public static int gcd(int a, int b) { return b==0 ? a : gcd(b,a%b); } 

} 

Answer 1

當你把兩個整數，你得到整數除法，與整數結果，即使你以後分配結果到double。嘗試

double reducedRatio = (double)reducedCount/nonReducedCount; 

即將其中一個操作數轉換爲double。