java - Java 中的数学计算不正确

Question

我这里遇到了一些麻烦。我正在制作一个数学程序，要求用户提供数学问题中要使用的位数。然后它会询问数学问题的类型，并询问用户 10 个问题。它检查答案是否正确并显示适当的消息。如果错误，用户可以永远重试该问题。然后，它会计算他们的得分是否超过 75% 并显示一条消息。

所有弹出窗口都工作得很好，但无论出于什么原因，它总是告诉我，无论我输入什么，答案都是错误的。我试图确保所有变量类型都匹配( double )，以便响应不会出现任何转换问题，但我是 Java 新手，所以我不知道我是否正确执行了此操作。

你们有机会发现我的代码的问题吗？任何帮助是极大的赞赏。感谢您的观看。

还要感谢那些已经帮助我解决了这个项目中其他问题的人，我仍在学习 Java!

import java.util.*;
import javax.swing.JOptionPane;
/**
 *
 */

/**
 * @author Tyler
 *
 */
public class Program {

        /**
         * @param args
         */
        public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input = new Scanner(System.in);
                int difficulty = 1;
                String[] operators = {"plus", "minus", "times", "divided by"};
                int selectedOperator = 1;
                int correctAnswers = 0;
                int answeredTyped = 0;

                int difficultyInput = Integer.parseInt(JOptionPane.showInputDialog("Please choose the difficulty. Enter the number of digits to use in each problem."));

if (difficultyInput > 0) {
        difficulty = difficultyInput;
}
int arithmeticMethod = Integer.parseInt(JOptionPane.showInputDialog("Choose an arithmetic problem to study: 1 = Addition Only, 2 = Subtraction Only, 3 = Multiplication Only, 4 = Division Only, 5 = Random Problems" ));

        selectedOperator = arithmeticMethod;

        new Program().askQuestion(difficulty, null, arithmeticMethod, arithmeticMethod, operators, arithmeticMethod); }





        public static boolean checkResponse (double primaryInt, double secondaryInt, String operatorText, double response){
              if (operatorText.equals("1")){
                  return (primaryInt + secondaryInt) == response;
              }
              else if (operatorText.equals("2")){
                  return (primaryInt - secondaryInt) == response;
              }
              else if (operatorText.equals("3")){
                  return (primaryInt * secondaryInt) == response;
              }
              else if (operatorText.equals("4")){
                  return (primaryInt / secondaryInt) == response;
              }
              return false;
        }




        public static String displayResponse (boolean isCorrect){
        int randomIndex = (int) (Math.floor(Math.random() * (4 - 1 + 1)) + 1);
        switch (randomIndex){
        case 1:
                return isCorrect ? "Very Good!" : "No. Please try again.";
        case 2:
                return isCorrect ? "Excellent!" : "Wrong. Try once more.";
        case 3:
                return isCorrect ? "Nice Work!" : "Don\'t give up!";
        case 4:
                return isCorrect ? "Keep up the good work!" : "No. Keep trying.";
        }
        return "Oops...";
}




        public static void askQuestion(int difficulty, String operatorText, int selectedOperator, int answeredTyped, String[] operators, int correctAnswers){
                boolean correctAnswer = false;
                double primaryInt = Math.floor(Math.pow(10,  difficulty-1) + Math.random() * 9 * Math.pow(10,  difficulty-1));
                double secondaryInt = Math.floor(Math.pow(10,  difficulty-1) + Math.random() * 9 * Math.pow(10, difficulty-1));
                operatorText = (selectedOperator == 5) ? operators[(int) Math.floor(Math.random() * operators.length)] : operators[selectedOperator - 1];

                while(!correctAnswer && answeredTyped < 10) {
                        double response = Double.parseDouble (JOptionPane.showInputDialog("How much is " + primaryInt + " " + operatorText + " " + secondaryInt + "?"));
                        correctAnswer = checkResponse (primaryInt, secondaryInt, operatorText, response);
                        JOptionPane.showMessageDialog(null, displayResponse(correctAnswer));

                        answeredTyped++;

                        if(correctAnswer)
                                correctAnswers++;
                }

        {

        while(answeredTyped < 10){
                askQuestion(0, null, 0, 0, null, 0);

        }

        if((correctAnswers / answeredTyped) >= 0.75) {
                JOptionPane.showMessageDialog(null, "Congratulations, you are ready to go on to the next level!");
        }
        else{
                        JOptionPane.showMessageDialog(null, "Please ask your teacher for extra help.");
        }
}
}
}

Answer 1

您正在进行整数除法，结果是整数，而不是浮点或 double 值。例如:

int a = 5;
int b = 2;
System.out.println(a / b); // will print 2
System.out.println((double)a / b); // will print 2.5