Java 實現大轉盤抽獎

注意：大轉盤抽獎各獎項中獎機率之和爲 1。獎品列表中的機率爲累加機率，須要按照添加進列表的順序進行累加，添加順序不作要求。java

實際中使用須要考慮獎品數量限制等業務需求，該代碼只是個簡單的抽獎demo。dom

獎品數量限制的話，若是須要保證剩餘獎品機率比例不變，須要從新構建獎品列表。函數

package com.wangbo.choujiang; import java.util.ArrayList; import java.util.List; import java.util.Random; /** * 大轉盤抽獎 * @author wangbo * @date 2019-05-22 14:54:47 */
public class Test1 { public static void main(String[] args) { 
        List<Award> awardList = new ArrayList<Award>(); Award award1 = new Award(); award1.setAwardName("手機");//10%
        award1.setProbability(0.1); awardList.add(award1); Award award2 = new Award(); award2.setAwardName("水杯");//20%
        award2.setProbability(0.2+0.1);//機率加上上一個獎品的機率（累加）
 awardList.add(award2); Award award4 = new Award(); award4.setAwardName("鼠標");//10%
        award4.setProbability(0.1+0.2+0.1); awardList.add(award4); Award award5 = new Award(); award5.setAwardName("謝謝惠顧");//60%
        award5.setProbability(1d);//最後一個確定是1
 awardList.add(award5); Random random = new Random(); int a = 0,b = 0,c = 0,d = 0; for (int i = 0; i < 10000; i++) { Double userSelect = random.nextDouble();//0.0-1.0的double隨機數（不包括1.0）
            String awardName = duageAward(userSelect, awardList); //信息統計
            if ("手機".equals(awardName)) { a++; }else if ("水杯".equals(awardName)) { b++; }else if ("鼠標".equals(awardName)) { c++; }else if ("謝謝惠顧".equals(awardName)){ d++; } } System.out.println("手機 " + a + " 次"); System.out.println("水杯 " + b + " 次"); System.out.println("鼠標 " + c + " 次"); System.out.println("謝謝惠顧 " + d + " 次"); } /** * 選獎品 * @param userSelect * @param awardList * @return
     */
    public static String duageAward(Double userSelect, List<Award> awardList){ for (Award award : awardList) { if(userSelect < award.getProbability()){ return award.getAwardName(); } } return null; } } class Award{ private String awardName; private Double probability; public String getAwardName() { return awardName; } public Double getProbability() { return probability; } public void setAwardName(String awardName) { this.awardName = awardName; } public void setProbability(Double probability) { this.probability = probability; } }

運行結果：this