Reading .txt file HELP

[husherwo]

I am given a .txt file and it contains two columns of multiple numbers separated by some spaces. The first column is an identification number while the following number in that row is a GPA. I need to find the average GPA for each identification number. An example is
1A 4.00
1A 3.79
1B 3.9
2A 4.0
2A 3.9

I need to categorize the averages by 1A, 1B, 2A, etc. I know how to input the text file but I am lost from there. I then need to categorize the GPA average from a certain GPA and up, such as all GPAs above a 3.5. Please help!

[PopEye]

This is a rough draft of the code resembling your request. You can modify it to your liking.

#include <iostream>
#include <stdlib.h>
#include <fstream>
#include <vector>
typedef unsigned short ushort;
using namespace std;

class Grades
{
    char average[3];
    float gpa;
    bool is1A, is1B, is2A;

    void assignBools();
public:
    Grades(const string&);

    string getAverage() const {return average;}
    float getGPA() const {return gpa;}
    bool getIs1A() const {return is1A;}
    bool getIs1B() const {return is1B;}
    bool getIs2A() const {return is2A;}
};

void mainMenu(vector <Grades>);

int main()
{
    ifstream iFile("grades.txt");
    vector <Grades> data;
    string line;

    if(iFile)
    {
        while(getline(iFile, line))
            data.push_back(Grades(line));

        iFile.close();
        mainMenu(data);
    }
    else
        cout << "Could not open file!\n";

    return 0;
}

Grades::Grades(const string& line)
{
    const ushort LINE_LENGTH = line.length();

    for(ushort i = 0; i < LINE_LENGTH; i++)
    {
        if(line[i] == ' ')
        {
            string floatHold;

            for(ushort j = i + 1; j < LINE_LENGTH; j++)
                floatHold += line[j];

            average[2] = '\0';
            gpa = atof(floatHold.c_str());
            break;
        }

        average[i] = line[i];
    }

    assignBools();
}
void Grades::assignBools()
{
    if(average[0] == '1' && average[1] == 'A')
    {
        is1A = true;
        is1B = false;
        is2A = false;
    }
    else if(average[0] == '1' && average[1] == 'B')
    {
        is1A = false;
        is1B = true;
        is2A = false;
    }
    else
    {
        is1A = false;
        is1B = false;
        is2A = true;
    }
}
void mainMenu(vector <Grades> data)
{
    const ushort VECTOR_SIZE = data.size();
    char main_menuAnswer;

    do
    {
        cout << "\t\t\tMAIN MENU v1.0\n\n-----\n1 - Search\n2 - Exit\n-----\nAnswer: ";
        cin >> main_menuAnswer;

        system("CLS");

        switch(main_menuAnswer)
        {
        case '1':
            {
                char search_menuAnswer;

                cout << "\t\t\tSEARCH MENU v1.0\n\nSearch by:\n-----\n1 - Average (e.g. 1A)\n2 - GPA\n-----\nAnswer: ";
                cin >> search_menuAnswer;

                system("CLS");

                switch(search_menuAnswer)
                {
                case '1':
                    {
                        string typedAverage;

                        cout << "\t\t\tAVERAGE SEARCH v1.0\n\nType Average to search: ";
                        cin >> typedAverage;
                        cout << "-----\n";

                        for(ushort i = 0, counter = 0; i < VECTOR_SIZE; i++)
                        {
                            if(typedAverage == data[i].getAverage())
                            {
                                counter++;
                                cout << data[i].getAverage() << ' ' << data[i].getGPA() << endl;
                            }

                            if(i == VECTOR_SIZE - 1 && counter == 0)
                                cout << "No data found for average: " << typedAverage << endl;
                        }

                        cout << "-----\n\n";
                        system("PAUSE");
                        system("CLS");
                        break;
                    }
                case '2':
                    {
                        float typedGPA;
                        char gpa_menuAnswer;

                        cout << "\t\t\tGPA SEARCH v1.0\n\nType GPA: ";
                        cin >> typedGPA;
                        cout << "-----\n1 - <\n2 - >\n3 - =\n-----\nAnswer: ";
                        cin >> gpa_menuAnswer;
                        cout << "\n-----\n";

                        for(ushort i = 0, counter = 0; i < VECTOR_SIZE; i++)
                        {
                            if(gpa_menuAnswer == '1')
                            {
                                if(typedGPA < data[i].getGPA())
                                {
                                    counter++;
                                    cout << data[i].getAverage() << ' ' << data[i].getGPA() << endl;
                                }
                            }
                            else if(gpa_menuAnswer == '1')
                            {
                                if(typedGPA > data[i].getGPA())
                                {
                                    counter++;
                                    cout << data[i].getAverage() << ' ' << data[i].getGPA() << endl;
                                }
                            }
                            else
                                if(typedGPA == data[i].getGPA())
                                {
                                    counter++;
                                    cout << data[i].getAverage() << ' ' << data[i].getGPA() << endl;
                                }

                            if(i == VECTOR_SIZE - 1 && counter == 0)
                                cout << "No data found for GPA: " << typedGPA << endl;
                        }

                        cout << "-----\n\n";
                        system("PAUSE");
                        system("CLS");
                    }
                }
            }
        }
    }while(main_menuAnswer != '2');
}

[dhayden]

To compute the average GPA, you'll need to keep track of the sum of the GPAs and the number of them.

// statistics
struct Stats {
    double sum;
    unsigned count;
    Stats() : sum(0), count(0) {;}
};

You need a way to look up one of these for each ID. A map is perfect for this:

#include <iostream>
#include <map>
#include <string>

using std::cout;
using std::cin;
using std::endl;
using std::map;
using std::string;

// statistics
struct Stats {
    double sum;
    unsigned count;
    Stats() : sum(0), count(0) {;}
};


typedef map<string,Stats> MyMap; // maps ID to statistics

int
main()
{
    MyMap theMap;
    string id;
    double gpa;

    while (cin >> id >> gpa) {
        Stats &s = theMap[id];  // find the Stats struct for the ID
        s.sum += gpa;           // adjust the gpa and count
        ++s.count;
    }

    cout << "ID\tAverage\n";
    for (auto &x : theMap) {
        Stats &s(x.second);
        cout << x.first << '\t' << s.sum / s.count << '\n';
    }

    return 0;
}