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

double* studentscores(char* key, char** student_answers, int numstud, int numq);
double best_grade(double* grades, int numStudents);
double lowest_grade(double* grades, int numStudents);
char score_to_letter_grade(double score);
void save_grades(char** studentIds, char** studentAnswers, double* grades, int numStudents, int idlen);
void display(char** studentIds, char** studentAnswers, double* grades, int numStudents, int idlen);

int main()
{
    int numStudents, idlen, numq;


    ifstream fin("hist101midterm1.txt");

    if (fin.fail())
    {
        cout << "Failed opening the file";
        exit(1);
    }

    fin >> numStudents >> idlen >> numq;

    char** studentIds = new char* [numStudents];
    char* key = new char[numq + 1];
    char** studentAnswers = new char* [numStudents];
    for (int i = 0; i < numStudents; i++)
    {
        studentAnswers[i] = new char[numq + 1];
        studentIds[i] = new char[idlen + 1];
    }

    fin >> key;

    for (int i = 0; i < numStudents; i++)
    {
        fin >> studentIds[i];
        fin >> studentAnswers[i];
    }

    double* grades = studentscores(key, studentAnswers, numStudents, numq);

    save_grades(studentIds, studentAnswers, grades, numStudents, idlen);
    display(studentIds, studentAnswers, grades, numStudents, idlen);

    delete[] grades;
    delete[] key;
    for (int i = 0; i < numStudents; i++) {
        delete[] studentIds[i];
        delete[] studentAnswers[i];
    }
    delete[] studentIds;
    delete[] studentAnswers;

    return 0;
}

double best_grade(double* grades, int numStudents) {
    double result = grades[0];
    for (int i = 1; i < numStudents; i++)
        if (result < grades[i])
            result = grades[i];
    return result;
}

double lowest_grade(double* grades, int numStudents) {
    double result = grades[0];
    for (int i = 1; i < numStudents; i++)
        if (result > grades[i])
            result = grades[i];
    return result;
}

char score_to_letter_grade(double score) {
    char result = '_';
    if (score >= 90)
        result = 'A';
    else if (score >= 80)
        result = 'B';
    else if (score >= 70)
        result = 'C';
    else if (score >= 60)
        result = 'D';
    else if (score >= 0)
        result = 'F';

    return result;
}


double* studentscores(char* key, char** student_answers, int numstud, int numq)
{
    double* score = new double[numstud];

    int numcorrect;

    for (int i = 0; i < numstud; i++)
    {
        numcorrect = 0;
        for (int j = 0; j < numq; j++)
            if (key[j] == student_answers[i][j])
                numcorrect++;

        score[i] = (double)numcorrect / numq * 100;
    }
    return score;
}


void save_grades(char** studentIds, char** studentAnswers, double* grades, int numStudents, int idlen)
{
    ofstream fout("saved.txt");

    double bestGrade = best_grade(grades, numStudents);
    double lowestGrade = lowest_grade(grades, numStudents);

    char* bestId = new char[idlen + 1];
    char* lowestId = new char[idlen + 1];

    fout << "Student ID\t------ Answers ----\tPercent\tGrade\n";
    for (int i = 0; i < numStudents; i++) {
        fout << studentIds[i] << "\t" << studentAnswers[i] << "\t";
        fout << grades[i] << "\t" << score_to_letter_grade(grades[i]) << endl;
    }

    fout << "Highest grade is " << bestGrade << " for student ";
    for (int i = 0; i < numStudents; i++)
        if (grades[i] == bestGrade)
            fout << studentIds[i] << " ";
    fout << endl;

    fout << "Lowest grade is " << lowestGrade << " for student ";
    for (int i = 0; i < numStudents; i++)
        if (grades[i] == lowestGrade)
            fout << studentIds[i] << " ";
    fout << endl;
    fout.close();

    delete[] bestId;
    delete[] lowestId;
}

void display(char** studentIds, char** studentAnswers, double* grades, int numStudents, int idlen)
{
    double bestGrade = best_grade(grades, numStudents);
    double lowestGrade = lowest_grade(grades, numStudents);

    char* bestId = new char[idlen + 1];
    char* lowestId = new char[idlen + 1];

    cout << "Student ID\t------ Answers ----\tPercent\tGrade\n";
    for (int i = 0; i < numStudents; i++) {
        cout << studentIds[i] << "\t" << studentAnswers[i] << "\t";
        cout << grades[i] << "\t" << score_to_letter_grade(grades[i]) << endl;
    }

    cout << "Highest grade is " << bestGrade << " for student ";
    for (int i = 0; i < numStudents; i++)
        if (grades[i] == bestGrade)
            cout << studentIds[i] << " ";
    cout << endl;

    cout << "Lowest grade is " << lowestGrade << " for student ";
    for (int i = 0; i < numStudents; i++)
        if (grades[i] == lowestGrade)
            cout << studentIds[i] << " ";
    cout << endl;

    delete[] bestId;
    delete[] lowestId;
}