隨機輸出，無法正常工作

我試圖編寫一個程序，選擇團隊隨機管理，但是當我運行它時，每次都得到相同的4個團隊而不是不同的團隊？隨機輸出，無法正常工作

我試圖讓它每次產生一個隨機數時都會進入一個數組。然後我會檢查該數組，看看數字是否曾經用過。

任何幫助或建議，將不勝感激。謝謝！

import java.util.*; 

class Start { 


    static String[] places = {"Man Utd", "Arsenal", "Aston Villa", "Chelsea", 
      "Everton", "Fulham", "Liverpool", "Man City", "Newcastle", "Norwich", 
      "QPR", "Reading", "Southampton", "Stoke", "Sunderland", "Swansea", 
      "Spurs", "West Brom", "West ham", "Wigan"}; 

    static int[] NA = {21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21}; 
    static Random rand = new Random(); 
    static int RandInt = 0; 
    static boolean x = false; 
    static boolean p = false; 
    static int player = 1; 

    public static void main(String[] args) { 

     while (x != true) { 

      RandInt = rand.nextInt(places.length); 
      for (int k = 0; k <= NA.length; k++) { 
       while (p != true) { 
        if (RandInt == NA[k]) { 
         RandInt = rand.nextInt(places.length); 
        } else { 
         p = true; 
         NA[k] = RandInt; 

        } 
       } 
       System.out.println("player " + player + " is managing " + places[RandInt]); 
       player++; 
       p = false; 
       if (player >= 5) { 
        x = true; 
        System.exit(0); 
       } 
      } 
     } 
    } 
}

來源

2014-05-03 sparky971

int [] NA是什麼意思？ – geoand

如果您使用答案，請選擇它。 – NonSecwitter

我「清理」了一下你的代碼，並且改變了數組來檢查重複的隨機數到一個ArrayList。這不是最快的解決方案，但它應該起作用。

問題是，在整個程序退出之前，您不會退出for循環。如上所述，RandInt == NA [k]永遠不會成立，因爲RandInt始終爲< = 19，因此不會生成新的隨機數。所以在代碼中有兩個錯誤的東西。

當你想了解更多更快的檢查重複條目，也許這將幫助你：http://javarevisited.blogspot.de/2012/02/how-to-check-or-detect-duplicate.html

我希望我可以幫助你。 :)

static String[] places = {"Man Utd", "Arsenal", "Aston Villa", "Chelsea", 
     "Everton", "Fulham", "Liverpool", "Man City", "Newcastle", "Norwich", 
     "QPR", "Reading", "Southampton", "Stoke", "Sunderland", "Swansea", 
     "Spurs", "West Brom", "West ham", "Wigan"}; 
static int[] NA = new ArrayList<Integer>(5); 
static Random rand = new Random(); 
static int RandInt = 0; 
static int player = 1; 

public static void main(String[] args) { 
    while (player < 5) { 
    RandInt = rand.nextInt(places.length); 

    for (int i = 0; i <= NA.size(); i++) { 
     if (RandInt == NA.get(i)) { 
     RandInt = rand.nextInt(places.length); 
     } else { 
     NA.add(RandInt); 
     break; 
     } 
    } 
    System.out.println("player " + player + " is managing " + places[RandInt]); 
    player++; 
    } 
    System.exit(0); 
}

來源

2014-05-03 21:00:18 TheFRedFox

的問題是，RandInt==NA[k]是不正確的（因爲RandomInt至多19由於places大小），因此RandomInt從不更新裏面的for循環。因爲for循環似乎做所有的工作while循環只執行一次

是好像你需要重新考慮你的隨機生成算法

來源

2014-05-03 13:01:52 geoand

RandInt在每次while循環迭代時更新 – NonSecwitter

只有一次 - 檢查代碼流，你會看到 – geoand

不，它會迭代4次，直到'player == 5'和'player'遞增並且在主'while'循環中測試 – NonSecwitter

我的建議是產生for循環內的隨機數，如圖低於

while (x != true) { 

      for (int k = 0; k <= NA.length; k++) { 
      RandInt = rand.nextInt(places.length); 
       while (p != true) { 
        if (RandInt == NA[k]) { 
         RandInt = rand.nextInt(places.length); 
        } else { 
         p = true; 
         NA[k] = RandInt; 

        } 
       } 
       System.out.println("player " + player + " is managing " + places[RandInt]); 
       player++; 
       p = false; 
       if (player >= 5) { 
        x = true; 
        System.exit(0); 
       } 
      }

來源

2014-05-03 13:31:33 NonSecwitter

隨機輸出，無法正常工作

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