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


struct Student
{
    int id;       //4 digit student id
    double score; //overall score as a percentage
    char grade;   //course letter grade

    double hw1;   //homework scores
    double hw2;
    double hw3;

    int qz1;      //quiz scores
    int qz2;
    int qz3;

    int mt;       //midterm score
    int fn;       //final score
};

const double HW_WEIGHT = 0.08;
const double QZ_WEIGHT = 0.15;
const double MT_WEIGHT = 0.31;
const double FN_WEIGHT = 0.46;

const double HW_TOT = 15.0;
const double QZ_TOT = 30.0;
const double MT_TOT = 100.0;
const double FN_TOT = 100.0;

void get_scores(Student& stud, ifstream& fin);
//preconditions: Passed Student object has been declared and the input file
//               has been connected to fin.
//postconditions: Scores for all assignments have been entered into
//                appropriate member variable and id has been entered.

void calc_grade(Student& stud);
//preconditions: Passed Student object has scores for all assignments.
//postconditions: score and grade has been calculated using global constants
//                for assignment weights.

void output_student(Student stud, ofstream& fout);
//preconditions: Student's scores and grades have been entered and calculated.
//postconditions: Student's scores and grades have been output in nice
//                format to the file connected to fout.

void output_heading(ofstream& fout);
//preconditions: fout has been succesfully opened for writing and no scores
//               have been written yet.
//postconditions: Properly formatted heading has been output to file. 



//You can put another function declaration here for a function that would calculate 
//and output the class avg and the number of each grade. This function would need to be passed
//the entire array along with the ofstream object for output.


int main()
{
    ifstream infile;
    ofstream outfile;
    
    infile.open("scores.txt");           // will need to change the name of this file for as8
    if (infile.fail())
    {
	cout << "Error opening input file\n";
	exit(1);
    }
    
    outfile.open("grades.txt");          // will need to change the name of this file for as8
    if (outfile.fail())
    {
	cout << "Error opening output file\n";
	exit(1);
    }

    Student student1;                    // need to declare an array of Students here

	output_heading(outfile);             // outputs heading for output file

	get_scores(student1, infile);        // These function calls get scores, calculate the grade,
	calc_grade(student1);                // and output the scores and grade for one student.
	output_student(student1, outfile);   // To do all this for a class, you could put these inside 
	                                     // a for loop and then you wouldn't have to make any changes
	                                     // to the functions. Each iteration of the for loop would
	                                     // take care of one student. Don't forget to change the 
	                                     // student1 variable to an element of the Student array.


	// after the for loop, you would then need to call the function that calculates the class
	// average and number of each grade.


	infile.close();
	outfile.close();

    return 0;
}



void get_scores(Student& stud, ifstream& fin)
{
    fin >> stud.id >> stud.hw1 >> stud.hw2 >> stud.hw3
        >> stud.qz1 >> stud.qz2 >> stud.qz3 >> stud.mt >> stud.fn;
}

void calc_grade(Student& stud)
{
    double hw_avg = (stud.hw1 + stud.hw2 + stud.hw3)/HW_TOT;
    double qz_avg = (stud.qz1 + stud.qz2 + stud.qz3)/QZ_TOT;

    stud.score = ( (qz_avg * QZ_WEIGHT) 
		 + (hw_avg * HW_WEIGHT)
		 + ((stud.mt / MT_TOT) * MT_WEIGHT) 
		 + ((stud.fn / FN_TOT) * FN_WEIGHT) ) * 100;
    
    if (stud.score >= 90)
    {
	stud.grade = 'A';
    }
    else if(stud.score >= 80)
    {
	stud.grade = 'B';
    }
    else if(stud.score >= 70)
    {
	stud.grade = 'C';
    }
    else if(stud.score >= 60)
    {
	stud.grade = 'D';
    }
    else
    {
	stud.grade = 'F';
    }
}

void output_student(Student stud, ofstream& fout)
{
    fout << setw(4) << stud.id
	 << setw(4) << stud.hw1
	 << setw(5) << stud.hw2
	 << setw(5) << stud.hw3
	 << setw(5) << stud.qz1
	 << setw(5) << stud.qz2
	 << setw(5) << stud.qz3
	 << setw(5) << stud.mt
	 << setw(5) << stud.fn
	 << setw(7) << static_cast<int>(stud.score)
     << setw(6) << stud.grade
	 << endl;
}

void output_heading(ofstream& fout)
{
    fout << setw(4) << "id "
	 << setw(5) << "HW 1"
	 << setw(5) << "HW 2"
	 << setw(5) << "HW 3"
	 << setw(5) << "Qz 1"
	 << setw(5) << "Qz 2"
	 << setw(5) << "Qz 3"
	 << setw(5) << "MT "
	 << setw(5) << "FN "
	 << setw(8) << "Course"
	 << setw(6) << "Grade"
	 << endl;

    fout << setw(4) << "----"
	 << setw(5) << "----"
	 << setw(5) << "----"
	 << setw(5) << "----"
	 << setw(5) << "----"
	 << setw(5) << "----"
	 << setw(5) << "----"
	 << setw(5) << "----"
	 << setw(5) << "----"
	 << setw(8) << "------"
	 << setw(6) << "-----"
	 << endl << endl;
}