java - 如何获取二维数组中每列相等匹配的数量？

Question

我有一个名为 CorrectAnswer 的数组，其中有 10 个值。每个值都是 A、B、C 或 D。

然后我有一个名为 StudentAnswers 的二维数组，它有 3 行和 10 列。我想创建一个方法来检查每列有多少个匹配项。

例如:

正确答案:[B、C、A、A、B、A、C、D、A、C]

学生 1 结果:C、D、C、D、B、D、C、C、A、B学生 2 结果:A、A、B、C、D、C、B、B、D、D学生 3 结果:A、C、C、C、B、C、A、A、A、A

然后它应该打印:

答案1:0答案2:1依此类推...直到达到 10，因为数组 CorrectAnswers 中有 10 个值

这是迄今为止我的代码:

private char[] correctAnswer = { 'B', 'C', 'A', 'A', 'B', 'A', 'C', 'D', 'A', 'C' };

private char[][] studentAnswers;

// constructor
    public MultipleChoice(int numberOfStudents) {
    studentAnswers = new char[numberOfStudents][10];
    for (int i = 0; i < studentAnswers.length; i++) {
        for (int j = 0; j < studentAnswers[i].length; j++) {
            int tal = (int) (Math.random() * 4);
            char c = (char) (tal + 'A');
            studentAnswers[i][j] = c;
        }
    }
}

// my method
public void printCorrectAnswerPrQuestion() {
    for (int i = 0; i < correctAnswer.length; i++) {

        System.out.print("number of correct answers to question number " + correctAnswer[i + 1] + ": ");
        int correctAnswers= 0;

        for (int j = 0; j < correctAnswer.length; j++) {
            if (correctAnswer[j] == studentAnswers[i][j]) {
                correctAnswers= correctAnswers+ 1;
            }
        }
        System.out.print(correctAnswers);
        System.out.println();
    }
}

Answer 1

外部 for 循环条件错误 i < correctAnswer.length 。一定是studentAnswers.length 。这将给出每个学生的正确答案数量。

<小时/>

如果您想知道正确回答问题的学生人数

for (int i = 0; i < correctAnswer.length; i++) {
    int correctAnswers = 0;
    System.out.print("number of correct answers to question number " + i + ": ");

    for (int j = 0; j < studentAnswers.length; j++) {
        if (correctAnswer[i] == studentAnswers[j][i]) {
            correctAnswers = correctAnswers + 1;
        }
    }
    System.out.println(correctAnswers);
}