C++

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File IO and Struct

Sep 19, 2019 at 8:43am
Orion98 (41)
I'm currently writing a program that consists of displaying students' ID, Name, Course, Credit, and Score. The data is all in this text file:

"StudentRecords.txt"
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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


The following table was used to calculate the GPA(just a reference):
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Range Grade:
90 -- 100 > 4.0
80 -- 89 > 3.0
70 -- 79 > 2.0
60 -- 69 > 1.0
0 -- 59 > 0.0


The problem I'm having right now is my output. I'm trying to get it to match my expected output, but I can't seem to figure it out. It probably has to do with some missing else if() statements in the second for loop.

If anyone can provide me some advice/hints on how to get my input to work and display my expected output, I would appreciate it!

My Current Code:
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#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;

struct Student
{
    int ID = -1;
    string Name = "";
    string Course = "";
    int Credit = -1;
    int Score = -1;
};

const int SIZE = 99;

int main()
{
    ifstream inputFile;
    string fileName = "StudentRecords.txt";
    Student studArr[SIZE];

    inputFile.open(fileName.c_str(), ios::in);

    int n = 0;

        if (inputFile.is_open())
        {
            while(!inputFile.eof())
            {
                Student st;
                inputFile >> st.ID;
                inputFile >> st.Name;
                inputFile >> st.Course;
                inputFile >> st.Credit;
                inputFile >> st.Score;
                studArr[n] = st;
                n++;
            }

            inputFile.close();
        }
        else
        {
            cout << "File cannot be opened.";
            return 1;
        }

        // sorts the array by ID and Course
        for (int i = 0; i < n; i++)
        {
            for(int j = i + 1; j < n; j++)
            {
                if(studArr[i].ID > studArr[j].ID)
                {
                    Student temp = studArr[i];
                    studArr[i] = studArr[j];
                    studArr[j] = temp;
                }
                else if(studArr[i].Course > studArr[j].Course)
                {
                    Student temp = studArr[i];
                    studArr[i] = studArr[j];
                    studArr[j] = temp;
                }
            }
        }

        int check = 0;
        float dividend = 0;
        float divisor = 0;
        for(int i = 0; i < n; i++)
        {
            if(studArr[i].ID != studArr[check].ID)
            {
                cout << "======================\nGPA " 
                     << round((dividend / divisor)) << endl;
            }
            else if() // possibility of error in current output
            {

            }
            else if() // possibility of error in current output
            {

            }
            else if(i == 0)
            {
                cout << studArr[i].ID << " " << studArr[i].Name << endl;
                dividend = 0;
                divisor = 0;
            }

            float gradepoints;
            if(studArr[i].Score < 60)
            {
                gradepoints = 0.0;
            }
            else if(studArr[i].Score < 70)
            {
                gradepoints = 1.0;
            }
            else if(studArr[i].Score < 80)
            {
                gradepoints = 2.0;
            }
            else if(studArr[i].Score < 90)
            {
                gradepoints = 3.0;
            }
            else if(studArr[i].Score < 100)
            {
                gradepoints = 4.0;
            }

            dividend += gradepoints * studArr[i].Credit;
            divisor += studArr[i].Credit;
            cout << studArr[i].Course << " " 
                 << studArr[i].Score << " " 
                 << gradepoints << endl;
        }
        cout << "======================\nGPA " 
             << round((dividend / divisor)) << endl;
        cout << endl;

        return 0;
}
Edit & run on cpp.sh


My Current Output:
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12546 Amy
CS1 81 3
CS2 90 4
CS3 90 4
======================
GPA 4
CS1 76 2
======================
GPA 3
CS2 85 3
======================
GPA 3
CS3 75 2
======================
GPA 3
CS1 64 1
======================
GPA 3
CS2 71 2
======================
GPA 3
CS3 69 1
======================
GPA 2
CS3 80 3
======================
GPA 3
CS3 45 0
======================
GPA 2


Expected Output:
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12546 Amy

CS1 4 81 3.0

CS2 4 90 4.0

CS3 3 90 4.0

======================

GPA 3.64

======================
13455 Bill

CS1 4 76 2.0

CS2 4 85 3.0

CS3 3 75 2.0

======================

GPA 2.36

======================
14328 Jim

CS1 4 64 1.0

CS2 4 71 2.0

CS3 3 69 1.0

======================

GPA 1.36

======================

14388 Henry

CS3 3 80 3.0

======================

GPA 3

======================
15667 Peter

CS3 3 45 0.0

======================

GPA 0
Last edited on Sep 20, 2019 at 10:52pm
Sep 19, 2019 at 8:47am
Repeater (3046)
Looks like every time you output an endl, you should have output TWO of them.
So do that. Everywhere you output an endl, add another.

Looks like every time you ouput gradepoints, you need it to be to one decimal place.

One way: https://stackoverflow.com/questions/5907031/printing-the-correct-number-of-decimal-points-with-cout

Another way (since the gradepoints is always an integer value):

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  divisor += studArr[i].Credit;
            cout << studArr[i].Course << " " 
                 << studArr[i].Score << " " 
                 << gradepoints << ".0" << endl;
Last edited on Sep 19, 2019 at 8:50am
Sep 19, 2019 at 9:07am
Orion98 (41)
That seemed to fix my gradepoints error and the structure of the output. Now I just need to figure out how to display the other students' ID, Name, Course, Credit, and Score as well as their GPA

Thanks for your help so far @Repeater!

My Updated Code:
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#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;

struct Student
{
    int ID = -1;
    string Name = "";
    string Course = "";
    int Credit = -1;
    int Score = -1;
};

const int SIZE = 99;

int main()
{
    ifstream inputFile;
    string fileName = "StudentRecords.txt";
    string token;
    Student studArr[SIZE];

    inputFile.open(fileName.c_str(), ios::in);

    int n = 0;

        if (inputFile.is_open())
        {
            while(!inputFile.eof())
            {
                Student st;
                inputFile >> st.ID;
                inputFile >> st.Name;
                inputFile >> st.Course;
                inputFile >> st.Credit;
                inputFile >> st.Score;
                studArr[n] = st;
                n++;
            }

            inputFile.close();
        }
        else
        {
            cout << "File cannot be opened.";
            return 1;
        }

        // sorts the array by ID and Course
        for (int i = 0; i < n; i++)
        {
            for(int j = i + 1; j < n; j++)
            {
                if(studArr[i].ID > studArr[j].ID)
                {
                    Student temp = studArr[i];
                    studArr[i] = studArr[j];
                    studArr[j] = temp;
                }
                else if(studArr[i].Course > studArr[j].Course)
                {
                    Student temp = studArr[i];
                    studArr[i] = studArr[j];
                    studArr[j] = temp;
                }
            }
        }

        int check = 0;
        float dividend = 0;
        float divisor = 0;
        for(int i = 0; i < n; i++)
        {
            if(studArr[i].ID != studArr[check].ID)
            {
                cout << "======================\nGPA " 
                       << round((dividend / divisor)) << endl << endl;
            }
            else if(i == 0)
            {
                cout << studArr[i].ID << " " << studArr[i].Name << endl << endl;
                dividend = 0;
                divisor = 0;
            }

            float gradepoints;
            if(studArr[i].Score < 60)
            {
                gradepoints = 0.0;
            }
            else if(studArr[i].Score < 70)
            {
                gradepoints = 1.0;
            }
            else if(studArr[i].Score < 80)
            {
                gradepoints = 2.0;
            }
            else if(studArr[i].Score < 90)
            {
                gradepoints = 3.0;
            }
            else if(studArr[i].Score < 100)
            {
                gradepoints = 4.0;
            }

            dividend += gradepoints * studArr[i].Credit;
            divisor += studArr[i].Credit;
            cout << studArr[i].Course << " " 
                   << studArr[i].Score << " " 
                   << gradepoints << ".0" << endl << endl;
        }
        cout << "======================\nGPA " 
               << round((dividend / divisor)) << endl << endl;
        cout << endl << endl;

        return 0;
}
Edit & run on cpp.sh


My Updated Output:
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12546 Amy

CS1 81 3.0

CS2 90 4.0

CS3 90 4.0

======================
GPA 4

CS1 76 2.0

======================
GPA 3

CS2 85 3.0

======================
GPA 3

CS3 75 2.0

======================
GPA 3

CS1 64 1.0

======================
GPA 3

CS2 71 2.0

======================
GPA 3

CS3 69 1.0

======================
GPA 2

CS3 80 3.0

======================
GPA 3

CS3 45 0.0

======================
GPA 2
Last edited on Sep 19, 2019 at 9:10am
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