随机生成方程及答案

bqucvtff  于 2021-07-13  发布在  Java
关注(0)|答案(2)|浏览(473)

我试图随机生成一个方程，也有50%的机会是错误的，并显示不正确的答案。不正确的答案应该有一个错误-2、-1、+1或+2。
有时我的代码会打印这样的除法方程（我不能发布图像）：2/10=13 1/5=43等等。
我搞不懂为什么这个等式显示的是一组没有一起检查的数字？
（它首先调用oncreateview方法中的generateEnumbers（）

  1. public void generateNumbers() {
  2.     //randomly generate 2 numbers and an operator
  3.     number1 = (int) (Math.random() * 10) + 1;
  4.     number2 = (int) (Math.random() * 10) + 1;
  5.     operator = (int) (Math.random() * 4) + 1;
  6.     //50% chance whether the displayed answer will be right or wrong
  7.     rightOrWrong = (int) (Math.random() * 2) + 1;
  8.     //calculate the offset of displayed answer for a wrong equation (Error)
  9.     error = (int) (Math.random() * 4) + 1;
  10.     generateEquation();
  11. }
  13. public void generateEquation() {
  14.     StringBuilder equation = new StringBuilder();
  15.     //append the first number
  16.     equation.append(number1);
  17.     //generate/append the operator and calculate the real answer
  18.     if (operator == 1) {
  19.         equation.append(" + ");
  20.         actualAnswer = number1 + number2;
  21.     } else if (operator == 2) {
  22.         equation.append(" - ");
  23.         actualAnswer = number1 - number2;
  24.     } else if (operator == 3) {
  25.         equation.append(" x ");
  26.         actualAnswer = number1 * number2;
  27.     } else if (operator == 4) {
  28.         if ((number1%number2==0) && (number1>number2)) {
  29.             actualAnswer = number1 / number2;
  30.         } else {
  31.             generateNumbers();
  32.         }
  33.         equation.append(" / ");
  35.     }
  36.     //append the second number and the equals sign
  37.     equation.append(number2 + " = ");
  39.     //we will display the correct answer for the equation
  40.     if (rightOrWrong == 1) {
  41.         displayedAnswer = actualAnswer;
  42.         equation.append(displayedAnswer);
  43.     }
  44.     //we will display an incorrect answer for the equation
  45.     //need to calculate error (-2, -1, +1, +2)
  46.     else {
  47.         if (error == 1) {
  48.             displayedAnswer = actualAnswer - 1;
  49.         } else if (error == 2) {
  50.             displayedAnswer = actualAnswer - 2;
  51.         }else if (error == 3) {
  52.             displayedAnswer = actualAnswer + 1;
  53.         }else {
  54.             displayedAnswer = actualAnswer + 2;
  55.         }
  56.         //append the displayed answer with error
  57.         equation.append(displayedAnswer);
  59.     }
  60.     questionNumber.setText("You have answered " + count + " out of 20 questions");
  61.     finalEquation.setText(equation.toString());
  62. }
JavaandroidRandomequation

2条答案

按热度按时间
xwmevbvl

xwmevbvl1#

我想你需要放一个 return 通话后的声明 generateNumbers 在

  1. } else if (operator == 4) {
  2.     if ((number1%number2==0) && (number1>number2)) {
  3.         actualAnswer = number1 / number2;
  4.     } else {
  5.         generateNumbers();
  6.     }
  7.     equation.append(" / ");
  9. }

因为这将重启整个过程，而不是继续增加数字。

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zysjyyx4

zysjyyx42#

更改代码以解决低概率除法问题：

  1. public void generateNumbers() {
  2.     number1 = (int) (Math.random() * 10) + 1;
  3.     number2 = (int) (Math.random() * 10) + 1;
  5.     //don't get operator here
  6.     //operator = (int) (Math.random() * 4) + 1;
  8.     rightOrWrong = (int) (Math.random() * 2) + 1;
  9.     error = (int) (Math.random() * 4) + 1;
  11.     //don't generate equation here, start (in the View with generateEquation instead of generate numbers
  12.     //generateEquation();
  13. }
  15. public void generateEquation() {
  16.     StringBuilder equation = new StringBuilder();
  17.     generateNumbers();
  19.     //determine operator here
  20.     operator = (int) (Math.random() * 4) + 1;
  22.     equation.append(number1);
  23.     if (operator == 1) {
  24.         equation.append(" + ");
  25.         actualAnswer = number1 + number2;
  26.     } else if (operator == 2) {
  27.         equation.append(" - ");
  28.         actualAnswer = number1 - number2;
  29.     } else if (operator == 3) {
  30.         equation.append(" x ");
  31.         actualAnswer = number1 * number2;
  32.     } else if (operator == 4) {
  33.         equation.append(" / ");
  34.         // generate new numbers if they are not suiteable
  35.         while((number1%number2!=0) && (number1<number2))
  36.         {
  37.             generateNumbers();
  38.         }
  39.         actualAnswer = number1 / number2;
  40.     }
  41.     ......
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