C++尝试按平均值对类数组进行排序，然后按递增顺序对它们进行排序

Question

这是类里面的一个项目，我被困了几个小时。作业是打开一个文本文件，其中包含学生姓名列表、他们的 ID 号以及他们在不同测验、期中考试和期末考试中的分数，然后计算平均值。我们必须为每个学生创建一个类(class)，然后计算每个学生的平均分，并根据谁获得最好的成绩给学生排名。到目前为止，我已经为每个学生创建了一个类(class)，找到了平均水平，并将学生的平均水平从高到低进行了排名，但我不知道如何分配排名。如果您想了解更多信息，这里是作业的图片:http://imgur.com/Jetvj7O

这是我的代码:

            #include <iostream>
            #include <cstring>
            #include <string>
            #include <fstream>
            #include <algorithm>
            #include <functional>
            using namespace std;

            int num_a = 0, num_b = 0, num_c = 0, num_d = 0, num_f = 0;

            class Student {
            private:
            int rank;
            string name;
            int id;
            double quiz_scores[5];
            double midterm_scores[2];
            double final_score;
            double average;
            double quiz_average;
            double midterm_average;
            char grade;


            public:
            Student();
            void setRank(int num);
            int getRank();
            void setGrade(double average);
            char getGrade();
            void setName(string first);
            string getName();
            void setId(int num);
            int getId();
            void setMidterms(double nums[]);
            double getMidterms();
            void setQuizes(double nums[]);
            double getQuizes();
            void setFinal(double num);
            double getFinal();
            void setAverage();
            double getAverage();

            };
            Student::Student()
            {
            name = "John Doe";
            id = 0;
            final_score = 0;
            average = 0;
            grade = 'F';
            midterm_scores[2] = {};
            quiz_scores[5] = {};
            rank = 0;
            }
            void Student::setRank(int num)
            {
                rank = num;
            }
            int Student::getRank()
            {
                return rank;
            }
            void Student::setGrade(double average)
            {
            if (average <= 100 && average >= 90)
            {
            grade = 'A';
            num_a++;
            }
            else if (average <= 89.99 && average >= 80)
            {
            grade = 'B';
            num_b++;
            }
            else if (average <= 79.99 && average >= 70)
            {
            grade = 'C';
            num_c++;
            }
            else if (average <= 69.99 && average >= 60)
            {
            grade = 'D';
            num_d++;
            }
            else if (average < 60)
            grade = 'F';
            num_f++;
            }
            void Student::setName(string first)
            {
            name = first;
            }
            string Student::getName()
            {
            return name;
            }
            void Student::setId(int num)
            {
            id = num;
            }
            int Student::getId()
            {
            return id;
            }
            void Student::setMidterms(double nums[])
            {
            cout.setf(ios::fixed);
            cout.setf(ios::showpoint);
            cout.precision(1);

            double average, sum = 0;
            for (int i = 0; i < 2; i++)
            {
            midterm_scores[i] = nums[i];
            sum += midterm_scores[i];
            }

            average = sum / 2;
            midterm_average = average * .40;

            }
            double Student::getMidterms()
            {
            return midterm_average;
            }
            void Student::setQuizes(double nums[])
            {
            cout.setf(ios::fixed);
            cout.setf(ios::showpoint);
            cout.precision(1);

            double score, sum = 0, average, min = nums[0];

            for (int i = 0; i < 5; i++)
            {
                if (nums[i] < min)
            {
            min = nums[i];
            }

            score = nums[i];
            quiz_scores[i] = score;
            sum += quiz_scores[i];
            }
            sum = sum - min;
            average = (sum / 40) * 100;
            quiz_average = average * .20 ;

            }
            double Student::getQuizes()
            {
            return quiz_average;
            }
            void Student::setAverage()
            {
            cout.setf(ios::fixed);
            cout.setf(ios::showpoint);
            cout.precision(1);

            average = (quiz_average + midterm_average + final_score);
            }
            void Student::setFinal(double num)
            {
            cout.setf(ios::fixed);
            cout.setf(ios::showpoint);
            cout.precision(1);

            final_score = num * .40;
            }
            double Student::getFinal()
            {
            return final_score;
            }
            double Student::getAverage()
            {
            return average;
            }

            char Student::getGrade()
            {
            return grade;
            }
            //ranks the student by decreasing average grade
            void rankStudents(double array[], int arraySize, Student scores[])
            {
                int m; // keep the index of current smallest value
                double newArray[30], hold, finalArray[30];
                bool isFound = false;
                //stores the averages in an array then sorts array
                for (int i = 0; i < arraySize; i++)
                {
                    newArray[i] = array[i];
                }

                for (int k = 0; k <= arraySize - 2; k++)
                {
                    m = k;
                    for (int j = k + 1; j <= arraySize - 1; j++)
                    {
                        if (newArray[j] > newArray[m])
                            m = j;
                    }

                    hold = newArray[m];
                    newArray[m] = newArray[k];
                    newArray[k] = hold;
                }

                //assigns rank to each student by comparing the array of averages to the students average by calling student.getAverage()
                for (int i = 0; i < arraySize; i++)
                {
                    double test = newArray[i];
                    int counter = i;
                    for (int k = 0; k < arraySize; k++)
                    {
                        int counter2 = i;
                        if (scores[k].getAverage() == test)
                        {
                            scores[k].setRank(counter+1);
                        }
                        else if (scores[k].getAverage() == scores[k - 1].getAverage() && scores[k].getAverage() == test)
                        {
                            scores[k].setRank(i + 1);
                            scores[k - 1].setRank(scores[k].getRank());
                        }
                        //cout << scores[k].getName() << ' ' << scores[k].getId() << ' ' << scores[k].getRank() << endl;
                    }
                }
                for (int i = 0; i < arraySize; i++)
                {
                    //cout << scores[i].getName() << ' ' << scores[i].getId() << ' ' << scores[i].getAverage() << ' ' << scores[i].getGrade() << ' ' << scores[i].getRank() << endl;
                }
                //creates finalArray which stores the students ranks and sorts them
                for (int i = 0; i < arraySize; i++)
                {
                    finalArray[i] = scores[i].getRank();
                }
                for (int k = 0; k <= arraySize - 2; k++)
                {
                    m = k;
                    for (int j = k + 1; j <= arraySize - 1; j++)
                    {
                        if (finalArray[j] < finalArray[m])
                            m = j;
                    }

                    hold = finalArray[m];
                    finalArray[m] = finalArray[k];
                    finalArray[k] = hold;
                }
                for (int i = 0; i < arraySize; i++)
                {
                    //cout << scores[i].getRank() << endl;
                }
                //prints out the array
                for (int i = 0; i < arraySize; i++)
                {
                    double test = newArray[i];
                    int counter3 = i;
                    for (int k = 0; k < arraySize; k++)
                    {
                        if (scores[k].getAverage() == test)
                        {
                            cout << scores[k].getName() << ' ' << scores[k].getId() << ' ' <<  scores[k].getAverage() << ' ' <<scores[k].getGrade() << ' ' << scores[k].getRank() << endl;
                        }
                        if (scores[k].getAverage() == scores[k - 1].getAverage() && scores[k].getAverage() == test)
                        {
                            scores[k].setRank(i + 1);
                            scores[k - 1].setRank(scores[k].getRank());
                            cout << scores[k].getName() << ' ' << scores[k].getId() << ' ' << scores[k].getAverage() << ' ' << scores[k].getGrade() << ' ' << scores[k].getRank() << endl;
                        }
                    }

                }


            }

            void readFile(Student people[])
            {
                //declares input file
                ifstream in_file;
                string user_file;
                int number_of_students, id;

                double quiz1, quiz2, quiz3, quiz4, quiz5, midterm1, midterm2, final_score, quizes[5], midterm[2], averages[30];
                string name;
                cout << "Enter an input file: ";
                cin >> user_file;

                in_file.open(user_file);
                if (in_file.fail())
                {
                    cout << "Error: file open failed \n" << endl;
                    exit(1);
                }

                //finds number of players in the array
                in_file >> number_of_students;


                //creates an array for scores then stores the id and scores of each player
                for (int i = 0; i < number_of_students; i++)
                {
                    in_file >> name >> id >> quiz1 >> quiz2 >> quiz3 >> quiz4 >> quiz5 >> midterm1 >> midterm2 >> final_score;
                    people[i].setName(name);
                    people[i].setId(id);
                    quizes[0] = quiz1;
                    quizes[1] = quiz2;
                    quizes[2] = quiz3;
                    quizes[3] = quiz4;
                    quizes[4] = quiz5;
                    midterm[0] = midterm1;
                    midterm[1] = midterm2;
                    people[i].setQuizes(quizes);
                    people[i].setMidterms(midterm);
                    people[i].setFinal(final_score);
                    //cout << array[i].getName() << " quiz average = " << array[i].getQuizes() << "midterm average = " << array[i].getMidterms() << "final = " << array[i].getFinal() << endl;
                    people[i].setAverage();
                    people[i].setGrade(people[i].getAverage());
                    //cout << array[i].getAverage() << endl;
                    averages[i] = people[i].getAverage();
                    //cout << averages[i] << endl;


                    //cout << "grade = " << array[i].getGrade() << endl;

                    //calls findAverage function to find average of each array then stores the result in player class



                }
                rankStudents(averages, number_of_students, people);

                for (int i = 0; i < number_of_students; i++)
                {
                    if (people[i].getAverage() == averages[i])
                        people[i].setRank(i);

                }
                for (int i = 0; i < number_of_students; i++)
                {
                    cout << people[i].getRank();
                }

            }
            int main()
            {

            Student students[30];
            readFile(students);




            return 0;
            }

这是我需要帮助的部分:

            void rankStudents(double array[], int arraySize, Student scores[])
            {
                int m; // keep the index of current smallest value
                double newArray[30], hold, finalArray[30];
                bool isFound = false;
                //stores the averages in an array then sorts array
                for (int i = 0; i < arraySize; i++)
                {
                    newArray[i] = array[i];
                }

                for (int k = 0; k <= arraySize - 2; k++)
                {
                    m = k;
                    for (int j = k + 1; j <= arraySize - 1; j++)
                    {
                        if (newArray[j] > newArray[m])
                            m = j;
                    }

                    hold = newArray[m];
                    newArray[m] = newArray[k];
                    newArray[k] = hold;
                }

                //assigns rank to each student by comparing the array of averages to the students average by calling student.getAverage()
                for (int i = 0; i < arraySize; i++)
                {
                    double test = newArray[i];
                    int counter = i;
                    for (int k = 0; k < arraySize; k++)
                    {
                        int counter2 = i;
                        if (scores[k].getAverage() == test)
                        {
                            scores[k].setRank(counter+1);
                        }
                        else if (scores[k].getAverage() == scores[k - 1].getAverage() && scores[k].getAverage() == test)
                        {
                            scores[k].setRank(i + 1);
                            scores[k - 1].setRank(scores[k].getRank());
                        }
                        //cout << scores[k].getName() << ' ' << scores[k].getId() << ' ' << scores[k].getRank() << endl;
                    }
                }
                for (int i = 0; i < arraySize; i++)
                {
                    //cout << scores[i].getName() << ' ' << scores[i].getId() << ' ' << scores[i].getAverage() << ' ' << scores[i].getGrade() << ' ' << scores[i].getRank() << endl;
                }
                //creates finalArray which stores the students ranks and sorts them
                for (int i = 0; i < arraySize; i++)
                {
                    finalArray[i] = scores[i].getRank();
                }
                for (int k = 0; k <= arraySize - 2; k++)
                {
                    m = k;
                    for (int j = k + 1; j <= arraySize - 1; j++)
                    {
                        if (finalArray[j] < finalArray[m])
                            m = j;
                    }

                    hold = finalArray[m];
                    finalArray[m] = finalArray[k];
                    finalArray[k] = hold;
                }
                for (int i = 0; i < arraySize; i++)
                {
                    //cout << scores[i].getRank() << endl;
                }
                //prints out the array
                for (int i = 0; i < arraySize; i++)
                {
                    double test = newArray[i];
                    int counter3 = i;
                    for (int k = 0; k < arraySize; k++)
                    {
                        if (scores[k].getAverage() == test)
                        {
                            cout << scores[k].getName() << ' ' << scores[k].getId() << ' ' <<  scores[k].getAverage() << ' ' <<scores[k].getGrade() << ' ' << scores[k].getRank() << endl;
                        }
                        if (scores[k].getAverage() == scores[k - 1].getAverage() && scores[k].getAverage() == test)
                        {
                            scores[k].setRank(i + 1);
                            scores[k - 1].setRank(scores[k].getRank());
                            cout << scores[k].getName() << ' ' << scores[k].getId() << ' ' << scores[k].getAverage() << ' ' << scores[k].getGrade() << ' ' << scores[k].getRank() << endl;
                        }
                    }

                }


            }

Answer 1

您可以使用 std sort() 函数对分数进行排序，方法是给它一个指向数组开头的迭代器作为第一个参数，并给它一个指向数组开头的迭代器数组的末尾作为第二个参数。更多关于 sort .

然后，您可以遍历排序后的平均分数，并根据递减的基础给出分数。例如，您的最高分将获得排名 1。转到下一个分数。检查分数是否与之前相同。如果是，给出相同的排名，否则，增加你的排名然后分配它。

您的排名函数有点复杂。我建议你把它分成三个部分。获取平均值，排序，然后排名。我会使用 vector 来进一步简化事情。我希望这会有所帮助:)