从math.random改变有利的随机整数

Question

我有以下代码：

public void onFinish() {
              int num;
              String outCome = "";
              for (int ii = 0; ii < 10; ii++) {
                  num = (int) (Math.random() * 100) % 3;

                  switch (num) {
                  case 0:
                      outCome = "ountcome1";
                      break;
                  case 1:
                      outCome = "outcome2";
                      break;
                  case 2:
                      outCome = "outcome3";
                      break;
             }
                text.setText(outCome);

我想要完成的是案例0有50％的机会发生，而案例1和2有25％的机会。

提前致谢！

Answer 1

使用：Random.nextInt(4)，在情况0,3中返回“ountcome1” 在案例1中返回“ountcome2”并在案例2中返回“ountcome3”：

            switch (num) {
              case 0:
              case 3:
                  outCome = "outcome1";
                  break;
              case 1:
                  outCome = "outcome2";
                  break;
              case 2:
                  outCome = "outcome3";
                  break;
              ...          

Answer 2

使用此：

  for (int ii = 0; ii < 10; ii++) {
              num = (int) (Math.random() * 100) % 4; //Use 4 instead of 3

              switch (num) {
              case 0:
                  outCome = "ountcome1";
                  break;
              case 1:
                  outCome = "outcome2";
                  break;
              case 2:
                  outCome = "outcome3";
                  break;
              case 3:
                  outCome = "ountcome1";
                  break;

         }

因此，这里有四种可能的结果。如果获得0或3，则输出ountcome1（50％概率），否则输出另外两个。

Answer 3

尝试使用此

public void onFinish() {
          int num;
          String outCome = "";
          for (int ii = 0; ii < 10; ii++) {


              Random x = new Random(Calendar.getInstance().getTimeInMilliSec());
              num = x.nextInt(4);
              switch (num) {
              case 0:
                  outCome = "ountcome1";
                  break;
              case 1:
                  outCome = "outcome2";
                  break;
              case 2:
                  outCome = "outcome3";
                  break;
              case 3:
                  outCome = "ountcome1";
                  break;
         }
            text.setText(outCome);