Question

在方法totalCorrect（）和totalIncorrect（）中，我设置了一个var累加器来计算有多少个问题是对还是错。由于某些原因，它将无法正确增加。该程序说用户得到了24或40个正确和不正确的信息...为什么它不能正确递增？

import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
public class driverExam {
public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    System.out.println("Driver's Test. Input your answers for the following 
10 Q's. ");
    System.out.println();

    String[] testAnswers = {"B","D","A","A","C","A","B","A","C","D"};
    int uT = testAnswers.length; 
    String[] userAnswers = new String[uT];

    int i =0;
    while(i<uT) {
        System.out.print("Question #"+(i+1)+": ");
        String userInput = in.nextLine();
        userInput = userInput.toUpperCase();
        if (userInput.equals("A")|| userInput.equals("B")|| 
    userInput.equals("C")
                || userInput.equals("D")) {
            userAnswers[i] = userInput;
            i++;
        }else {
            System.out.println("Enter again: ");
        }
    }           

    System.out.println("Here are the results.");
    int qRight = totalCorrect(userAnswers,testAnswers);
    System.out.println("Total Correct: "+qRight);
    int qWrong = totalIncorrect(userAnswers, testAnswers);
    System.out.println("Total Incorrect: "+qWrong);
    System.out.println(passed(qRight));

    }

仅在数组发现userAnswers中的String在testAnswers中相同且在后一种方法中的var“ wrong”相同时，我才尝试增加var“ same”。

    /**
    * @param user
    * @param test
    * @return
    */
public static int totalCorrect(String[] user,String[] test) {
    int same=0;
    for (int r = 0;r<=user.length-1;r++) {
        for (int k =0;k<=test.length-1;k++) {
            if(user[r].equals(test[k])) {
                same++;
            }
        }
    }
    return same;    
}

/**
 * @param user
 * @param test
 * @return 
 */
public static int totalIncorrect(String[] user,String[] test) {
    int z=0;
    int wrong = 0;
    boolean isValid = true;
    while (isValid && z<user.length) {
        if (user[z]!=test[z]) {
            isValid = false;
            wrong ++;
            z++;
        }
        }
    return wrongQ;
    }

/**
 * @param numRight
 * @return //returns whether student has passed or failed
 */
public static String passed(int numRight) {
    int goldenNum = 8;
    if (numRight >=goldenNum) {
        return ("You passed.");
    }else
        return ("You have failed.");
}

/**
 * @param user
 * @param test
 * @return
 */
public static int[] questionMissed(String[] user, String[] test) {
    //return array which display which questions were missed
}
}

Answer 1

您正在检查每个用户答案是否与任何测试答案匹配。您只能将其与单个答案进行比较：

public static int totalCorrect(String[] user,String[] test) {
    int same=0;
    for (int r = 0;r<=user.length-1;r++) {
        if(user[r].equals(test[r])) {
            same++;
        }
    }
    return same;    
}

总的错误答案应该只是所有答案和正确答案之间的差，因此您不需要为此使用单独的方法。

int qWrong = userAnswers.length - qRight;

Answer 2

您只需要1个循环即可检查2个数组（如果它们的大小相同）：

public static int totalCorrect(String[] user,String[] test) {
    int qRight = 0;
    for (int i = 0;i<user.length;i++) {
        if(user[i].equals(test[i])) {
            qRight++;
        }
    }
    return qRight;    
}

public static int totalIncorrect(String[] user,String[] test) {
    int qWrong=0;
    for (int i = 0;i<user.length;i++) {
        if(!user[i].equals(test[i])) {
            qWrong++;
        }
    }
    return qWrong;    
}

或者您可以重复使用totalCorrect方法：

public static int totalIncorrect(String[] user,String[] test) {
    int qRight=totalCorrect(user,test);

    return test.length - qRight;    
}

比较数组-方法中的累加器不会增加

2 个答案: