Question

我正在为一个使用文件数据（学生成绩）的课程编写程序，然后根据最高等级到最低等级对其进行平均和组织。我几乎完成了，除了第46行的错误，它不会调用方法： findMaxIndex(courseGrade);

非常感谢任何帮助！

package project3;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

/**
 *
 * @author badluckbowers
 */
public class Project3 {

    final static int NUM_STUDENTS = 16;
    public static String[] nameArray = new String[NUM_STUDENTS];
    public static double[] labAvg = new double[NUM_STUDENTS];
    public static double[] quizAvg = new double[NUM_STUDENTS];
    public static double[] projectAvg = new double[NUM_STUDENTS];
    public static double[] examAvg = new double[NUM_STUDENTS];
    public static double[] finalExamArray = new double[NUM_STUDENTS];
    public static double[] courseGrade = new double[NUM_STUDENTS];
    public static char[] gradeArray = new char[NUM_STUDENTS];

    /**
     * @param args the command line arguments
     */
    final static int numLabScores = 15;
    final static int pointsLabPossible = 10;
    final static int numQuizScores = 12;
    final static int pointsQuizPossible = 5;
    final static int numProjectScores = 6;
    final static int pointsProjectPossible = 25;
    final static int numExamScores = 2;
    final static int pointsExamPossible = 100;
    final static int numFinalExamScores = 1;
    final static int pointsFinalExamPossible = 100;

    public static void main(String[] args) throws FileNotFoundException {

        readFile("scores.txt", nameArray, labAvg, quizAvg, projectAvg, examAvg, finalExamArray);

        findMaxIndex(courseGrade); 

        printArray();

    }

    public static void readFile(String fileName, String[] nameArray, double[] labAvg, double[] quizAvg, double[] projectAvg, double[] examAvg, double[] finalExamArray) throws FileNotFoundException {
        File input = new File(fileName);
        if (!input.exists()) {
            System.out.println("Error opening scores.txt for input; "
                    + "aborting program run.");
            System.exit(0);
        }
        Scanner inputFile = new Scanner(input);

        for (int i = 0; i < NUM_STUDENTS; i++) {
            nameArray[i] = inputFile.nextLine();
            labAvg[i] = calculatePercent(inputFile, numLabScores, pointsLabPossible); //15-1
            quizAvg[i] = calculatePercent(inputFile, numQuizScores, pointsQuizPossible);  //12-1
            projectAvg[i] = calculatePercent(inputFile, numProjectScores, pointsProjectPossible);  //6-1
            examAvg[i] = calculatePercent(inputFile, numExamScores, pointsExamPossible); //2-1
            finalExamArray[i] = calculatePercent(inputFile, numFinalExamScores, pointsFinalExamPossible);  //1-1
            courseGrade[i] = calculateGrade(labAvg[i], quizAvg[i], projectAvg[i], examAvg[i], finalExamArray[i]);
            gradeArray[i] = calculateLetter(courseGrade[i]);

            inputFile.nextLine();

        }

        inputFile.close();

    }

    public static double calculatePercent(Scanner inFile, int numScores, int pointsPossible) {
        double score;
        double total = 0;

        for (int i = 0; i < numScores; i++) {
            score = inFile.nextDouble();
            total += score;
        }
        return (total / (numScores * pointsPossible)) * 100;
    }

    public static double calculateGrade(double labAvg, double quizAvg, double projectAvg, double examAvg, double finalExamArray) {

        return ((labAvg * .15 + quizAvg * .10 + projectAvg * .25 + examAvg * .30 + finalExamArray * .20));

    }

    public static char calculateLetter(double courseGrade) {
        if (courseGrade < 60.0) {
            return 'F';
        } else if (courseGrade >= 60.0 && courseGrade < 70.0) {
            return 'D';
        } else if (courseGrade >= 70.0 && courseGrade < 80.0) {
            return 'C';
        } else if (courseGrade >= 80.0 && courseGrade < 90) {
            return 'B';
        }
        return 'A';

    }

    //__________________________________________________________________________
    // sort stuff
    /**
     * finds index of smallest element in the part of the array bounded by start
     * and array.length-1
     *
     * @param courseGrade is fully populated
     * @param start is index to begin searching for smallest element
     * @return index of smallest item between start and array.length-1
     * @throws java.io.FileNotFoundException
     */
    public static double findMaxIndex(double[] courseGrade, int start) throws FileNotFoundException {
        int maxIndex;

        maxIndex = start;

        for (int index = start + 1; index < courseGrade.length; index++) {
            if (courseGrade[index] > courseGrade[maxIndex]) {
                maxIndex = index;
            }
        }

        return maxIndex;
    }

    /**
     * the items in the array will be sorted largest to smallest
     *
     * @param courseGrade
     * @throws java.io.FileNotFoundException
     */
    public static void sortArray(double[] courseGrade) throws FileNotFoundException {
        int maxIndex;
        double maxItem;

        for (int i = 0; i > courseGrade.length - 1; i++) {
            maxIndex = (int) findMaxIndex(courseGrade, i);

            //put the smaller item in place of the current item
            maxItem = courseGrade[maxIndex];
            courseGrade[maxIndex] = courseGrade[i];
            courseGrade[i] = maxItem;

            System.out.println("Array after pass " + (i + 1) + " of selection sort:");
            for (int j = 0; j < courseGrade.length; j++) {
                System.out.print(courseGrade[j] + "  ");
            }
            System.out.println("");

        }
    }

    //__________________________________________________________________________
    public static void printArray() {
        System.out.println("The array elements are: ");
        for (int i = 0; i < nameArray.length; i++) {
            System.out.println(nameArray[i] + "  " + labAvg[i] + "  " + quizAvg[i] + "  " + projectAvg[i] + "  " + examAvg[i] + "  " + finalExamArray[i] + "  " + courseGrade[i] + "  " + gradeArray[i]);
        }
        System.out.println();
    }

}

Answer 1

调用函数findMaxIndex(courseGrade, startIndex);时需要传递第二个参数。因为你的函数定义有两个参数。

def connect_db():
    conn = sqlite3.connect(app.config['DATABASE'])
    conn.row_factory = sqlite3.Row
    return conn


def init_db():
    conn = connect_db()
    cursor = conn.cursor()
    sql = 'create table if not exists users (id integer primary key autoincrement, username text not null, password text not null, admin boolean not null)'
    cursor.execute(sql)
    conn.commit()

方法不能应用于java中的给定类型

1 个答案: