如何修复学生成绩计划的GPA输出

时间：2019-09-24 21:31:15

标签： c++

在我以前的文章中，我需要有关正在编写的程序的一些代码的帮助，该程序可以从.txt文件输出带有每个学生的ID，姓名，课程，学分，分数和GPA的数据。

StudentRecords.txt 

12546 Amy   CS1 4 81 
13455 Bill  CS1 4 76
14328 Jim   CS1 4 64
14388 Henry CS3 3 80
15667 Peter CS3 3 45
12546 Amy   CS2 4 90 
13455 Bill  CS2 4 85
14328 Jim   CS2 4 71

12546 Amy   CS3 3 90 
13455 Bill  CS3 3 75
14328 Jim   CS3 3 69

下表用于计算GPA（仅供参考）：

Range Grade:
90 -- 100 > 4.0
80 -- 89 > 3.0
70 -- 79 > 2.0
60 -- 69 > 1.0
0 -- 59 > 0.0

建议我使用向量而不是数组。所以我重写了我的程序。

我能够以有组织的数据结构输出每个学生的ID，姓名，课程，学分和分数。但是，我的GPA不适用于每个学生。

我试图将int grade与denominator += records[i].Courses[j].Credit;和numerator += records[i].Courses[j].Credit;都乘以，但是没有成功。

如果有人可以帮助我，我将不胜感激！

我当前的代码：

#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

struct Course
{
    string CourseName;
    int Credit;
    int Score;
};

struct Student
{
    int ID;
    string Name;
    vector<Course> Courses;
};

int locateStudent(int id, vector<Student> records);

int main()
{
    fstream inputFile;
    string fileName = "StudentRecords.txt";
    inputFile.open(fileName.c_str(), ios::in);

    int stuList;
    int uniqueID;
    Course tempCourse;

    string name;
    string courseNm;
    int credit;
    int score;

    vector<Student> records;

        if (inputFile.is_open())
        {
            while(!inputFile.eof())
            {
                inputFile >> uniqueID;
                stuList = locateStudent(uniqueID, records);

                if (stuList == -1)
                {
                    Student tempSt;
                    tempSt.ID = uniqueID;
                    inputFile >> tempSt.Name >> courseNm >> credit >> score;
                    tempCourse = {courseNm, credit, score};

                    tempSt.Courses.push_back(tempCourse);
                    records.push_back(tempSt);
                }
                else
                {
                    inputFile >> name;
                    inputFile >> courseNm >> credit >> score;
                    tempCourse = {courseNm, credit, score};
                    records[stuList].Courses.push_back(tempCourse);
                }
            }
            inputFile.close();
        }
        else
        {
            cout << "File cannot be opened.";
        }


        for (unsigned int i = 0; i < records.size(); i++)
        {
            cout << records[i].ID << "\n" << records[i].Name << "\n";
            cout << "==========\n";

            int numerator = 0;
            int denominator = 0;
            for (unsigned int j = 0; j < records[i].Courses.size(); j++)
            {
                int curScore = records[i].Courses[j].Score;
                cout << records[i].Courses[j].CourseName << "  ";
                cout << records[i].Courses[j].Credit << "  ";
                int grade = curScore == 100 ? 4 : (curScore);
                cout << grade << "\n";

                numerator += records[i].Courses[j].Credit;
                denominator += records[i].Courses[j].Credit;
            }

            cout << "==========\n";
            cout << "GPA: " << (double)numerator / denominator << "\n\n";
        }
}

int locateStudent(int uniqueID, vector<Student> records)
{
    int curID;
    for (unsigned int check = 0; check < records.size(); check++)
    {
        curID = records[check].ID;
        if (uniqueID == curID)
        {
            return check;
        }
    }

    return -1;
}

我当前的输出：

12546
Amy
==========
CS1  4  81
CS2  4  90
CS3  3  90
==========
GPA: 1

13455
Bill
==========
CS1  4  76
CS2  4  85
CS3  3  75
==========
GPA: 1

14328
Jim
==========
CS1  4  64
CS2  4  71
CS3  3  69
==========
GPA: 1

14388
Henry
==========
CS3  3  80
==========
GPA: 1

15667
Peter
==========
CS3  3  45
==========
GPA: 1

预期输出：

12546
Amy
==========
CS1  4  81
CS2  4  90
CS3  3  90
==========
GPA: 3.64

13455
Bill
==========
CS1  4  76
CS2  4  85
CS3  3  75
==========
GPA: 2.36

14328
Jim
==========
CS1  4  64
CS2  4  71
CS3  3  69
==========
GPA: 1.36

14388
Henry
==========
CS3  3  80
==========
GPA: 3

15667
Peter
==========
CS3  3  45
==========
GPA: 0

2 个答案:

答案 0 :(得分：0)

您正在尝试计算加权平均值，其中权重为功劳。分母是正确的：它是所有权重的总和。但是，分子是错误的：应该是每个分数的总和乘以其相应的权重。

这将为您提供0到100之间的平均分数（因为所有分数都属于此范围）；因此最后必须将其缩小以使其介于0到4（GPA的值范围）之间。

结果代码如下：

int numerator = 0;
int denominator = 0;
for (unsigned int j = 0; j < records[i].Courses.size(); j++)
{
    int curScore = records[i].Courses[j].Score;
    int curCredit = records[i].Courses[j].Credit;
    cout << records[i].Courses[j].CourseName << "  ";
    cout << curCredit << "  ";
    cout << curScore << "\n";

    numerator += curScore * curCredit;
    denominator += curCredit;
}

cout << "==========\n";
cout << "GPA: " << (double)numerator / denominator / 25.0 << "\n\n";

答案 1 :(得分：0)

我知道了！感谢@ Code-Apprentice的帮助！我编写了float mapGPA (int Score)函数，该函数将有助于计算我的GPA以及添加头文件#include <iomanip>以便为GPA安排小数。

我的更新代码：

#include <iostream>
#include <fstream>
#include <vector>
#include <iomanip>
using namespace std;

struct Course
{
    string CourseName;
    int Credit;
    int Score;
};

struct Student
{
    int ID;
    string Name;
    vector<Course> Courses;
};

float mapGPA (int Score)
{
    if (Score < 60)
    {
        return 0;
    }
    else if (Score < 70)
    {
        return 1;
    }
    else if (Score < 80)
    {
        return 2;
    }
    else if (Score < 90)
    {
        return 3;
    }
    else if (Score <= 100)
    {
        return 4;
    }

    return 0;
}

int locateStudent(int id, vector<Student> records);

int main()
{
    fstream inputFile;
    string fileName = "StudentRecords.txt";
    inputFile.open(fileName.c_str(), ios::in);

    int stList;
    int uniqueID;
    Course tempCourse;

    string name;
    string courseNm;
    int credit;
    int score;

    vector<Student> records;

        if (inputFile.is_open())
        {
            while(!inputFile.eof())
            {
                inputFile >> uniqueID;
                stList = locateStudent(uniqueID, records);

                if (stList == -1)
                {
                    Student tempSt;
                    tempSt.ID = uniqueID;
                    inputFile >> tempSt.Name >> courseNm >> credit >> score;
                    tempCourse = {courseNm, credit, score};

                    tempSt.Courses.push_back(tempCourse);
                    records.push_back(tempSt);
                }
                else
                {
                    inputFile >> name;
                    inputFile >> courseNm >> credit >> score;
                    tempCourse = {courseNm, credit, score};
                    records[stList].Courses.push_back(tempCourse);
                }
            }
            inputFile.close();
        }
        else
        {
            cout << "File cannot be opened.";
        }


        for (unsigned int i = 0; i < records.size(); i++)
        {
            cout << records[i].ID << "\n" << records[i].Name << "\n";
            cout << "==========\n";

            int numerator = 0;
            int denominator = 0;
            for (unsigned int j = 0; j < records[i].Courses.size(); j++)
            {
                int curScore = records[i].Courses[j].Score;
                cout << records[i].Courses[j].CourseName << "  ";
                cout << records[i].Courses[j].Credit << "  ";
                int curGrade = curScore == 100 ? 4 : (curScore);
                cout << curGrade << "\n";

                cout << setprecision(3);
                numerator += records[i].Courses[j].Credit * mapGPA(curScore);
                denominator += records[i].Courses[j].Credit;
            }

            cout << "==========\n";
            cout << "GPA: " << (double)numerator / denominator << "\n\n";
        }
}

int locateStudent(int uniqueID, vector<Student> records)
{
    int curID;
    for (unsigned int check = 0; check < records.size(); check++)
    {
        curID = records[check].ID;
        if (uniqueID == curID)
        {
            return check;
        }
    }

    return -1;
}

我的更新输出：

12546
Amy
==========
CS1  4  81
CS2  4  90
CS3  3  90
==========
GPA: 3.64

13455
Bill
==========
CS1  4  76
CS2  4  85
CS3  3  75
==========
GPA: 2.36

14328
Jim
==========
CS1  4  64
CS2  4  71
CS3  3  69
==========
GPA: 1.36

14388
Henry
==========
CS3  3  80
==========
GPA: 3

15667
Peter
==========
CS3  3  45
==========
GPA: 0
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