#include <iostream>
#include <string>
#include <fstream>
#include <iomanip>

using namespace std; 

const int NUM_STUDENTS = 25; 
const int NUM_ANSWERS = 30; 
const char EOLN = '\n'; 
const string LINE = "========================="; 
const int OPTION_MIN = 0; 
const int OPTION_MAX = 3; 

typedef char AnsList [NUM_ANSWERS]; 
struct StudentInfo
{
	string name; 
	AnsList ans_list; 
	int grade; 
	bool invalid; 
}; 
typedef StudentInfo StudentInfoList [NUM_STUDENTS]; 

int read_data(AnsList, StudentInfoList); 
void print_data(const StudentInfoList); 
void printf_keys(const AnsList); 
void sort_data_by_grade(StudentInfoList); 
void sort_data_by_name(StudentInfoList); 
int manu(); 

int main()
{
	StudentInfoList stud_info_list; 	
	AnsList keys; 
	int read_file_status; 
	int option; 

	read_file_status = read_data(keys, stud_info_list); 

	do{
		option = manu(); 

		switch (option)
		{
		case 1: 
			sort_data_by_grade(stud_info_list); 
			print_data(stud_info_list); 
			break; 
		case 2: 
			sort_data_by_name(stud_info_list); 
			print_data(stud_info_list); 
			break; 
		case 3: 
			printf_keys(keys); 
			break; 
		}
	} while (option != 0); 
	cout << endl << "Exit the program ..." << endl << endl; 

	return read_file_status; 
}

//////////////////////////////////////////////////////////////////////////
int read_data(AnsList keys, StudentInfoList stud_info_list)
{
	const string fname = "xfile.txt"; 

	ifstream inFile; 
	int ii, jj; 

	inFile.open(fname); 
	if (!inFile)
	{
		cout << "Error: file open fails!" << endl; 
		return (EXIT_FAILURE); 
	}
	else
		cout << "Loading data ..."; 

	for (ii=0; ii<NUM_ANSWERS; ii++)
		inFile >> keys[ii]; 

	inFile.ignore(100, EOLN); 

	for (jj=0; jj<NUM_STUDENTS; jj++)
	{
		stud_info_list[jj].grade = 0; 
		stud_info_list[jj].invalid = false; 

		getline(inFile, stud_info_list[jj].name); 
		for (ii=0; ii<NUM_ANSWERS; ii++)
		{
			inFile >> stud_info_list[jj].ans_list[ii]; 
			
			if ((stud_info_list[jj].ans_list[ii] != 'T') &&
				(stud_info_list[jj].ans_list[ii] != 'F'))
				stud_info_list[jj].invalid = true;
			else
				if (stud_info_list[jj].ans_list[ii] ==
					keys[ii])
					stud_info_list[jj].grade++; 

		}
		inFile.ignore(100, EOLN); 
	}
	cout << "Done!" << endl << endl; 

	inFile.close(); 
	return 0; 
}

//////////////////////////////////////////////////////////////////////////
void print_data(const StudentInfoList stud_info_list)
{
	int ii, jj; 

	cout << left; 
	cout << setw(20) << "NAME"; 
	cout << setw(35) << "ANSWERS"; 
	cout << setw(10) << "GRADES"; 
	cout << setw(20) << "INVALID ANSWER?" << endl; 
	cout << LINE << LINE << LINE << endl; 
	for (jj=0; jj<NUM_STUDENTS; jj++)
	{
		cout << setw(20) << stud_info_list[jj].name; 
		for (ii=0; ii<NUM_ANSWERS; ii++)
			cout << stud_info_list[jj].ans_list[ii]; 
		cout << "     "; 
		cout << setw(10) << stud_info_list[jj].grade; 
		if (stud_info_list[jj].invalid)
			cout << setw(20) << "Yes" << endl; 
		else
			cout << setw(20) << "No" << endl; 
	}

	cout << endl; 
}

//////////////////////////////////////////////////////////////////////////
void sort_data_by_grade(StudentInfoList stud_info_list)
{
	int i_current,				// index of current entry
		i_compare,				// index of curretly compared entry
		i_highest;				// index of the highest entry so far
	StudentInfo tmp_student;	// temporary struct for swtiching the order
	
	for (i_current = 0; i_current<NUM_STUDENTS; i_current++)
	{
		// initilize the highest grade in the unsorted part of the list
		i_highest = i_current; 

		// search the unsorted part of the list for the highest grade
		for (i_compare = i_current+1; i_compare<NUM_STUDENTS; i_compare++)
		{
			if (stud_info_list[i_highest].grade < 
				stud_info_list[i_compare].grade)
				i_highest = i_compare; 
		}

		// switch the entry containing the highest grade in the unsorted
		// list with the first entry of the unsorted part
		if (i_highest != i_current)
		{
			tmp_student = stud_info_list[i_current]; 
			stud_info_list[i_current] = stud_info_list[i_highest]; 
			stud_info_list[i_highest] = tmp_student; 
		}
	}
}

//////////////////////////////////////////////////////////////////////////
void sort_data_by_name(StudentInfoList stud_info_list)
{
	int i_current,				// index of current entry
		i_compare,				// index of curretly compared entry
		i_lowest;				// index of the lowest entry so far
	StudentInfo tmp_student;	// temporary struct for swtiching the order
	
	for (i_current = 0; i_current<NUM_STUDENTS; i_current++)
	{
		// initilize the lowest name in the unsorted part of the list
		i_lowest = i_current; 

		// search the unsorted part of the list for the lowest name
		for (i_compare = i_current+1; i_compare<NUM_STUDENTS; i_compare++)
		{
			if (stud_info_list[i_lowest].name > 
				stud_info_list[i_compare].name)
				i_lowest = i_compare; 
		}

		// switch the entry containing the lowest name in the unsorted
		// list with the first entry of the unsorted part
		if (i_lowest != i_current)
		{
			tmp_student = stud_info_list[i_current]; 
			stud_info_list[i_current] = stud_info_list[i_lowest]; 
			stud_info_list[i_lowest] = tmp_student; 
		}
	}
}

//////////////////////////////////////////////////////////////////////////
int manu()
{
	int option; 

	cout << "====================" << endl; 
	cout << "Menu" << endl; 
	cout << "====================" << endl; 
	cout << "[1] Sort by grade" << endl; 
	cout << "[2] Sort by name" << endl; 
	cout << "[3] Print out keys" << endl; 
	cout << "[0] Quit" << endl; 
	cout << "--------------------" << endl; 
	cout << "Your option is -> "; 
	cin >> option; 
	
	while(option < OPTION_MIN || option > OPTION_MAX)
	{
		cout << "Invalid option! Please re-enter your option -> "; 
		cin.clear(); 
		cin.ignore(100, '\n'); 
		cin >> option; 
	}

	return option; 
}

//////////////////////////////////////////////////////////////////////////
void printf_keys(const AnsList keys)
{
	cout << "KEYS: " << endl; 
	for (int ii = 0; ii < NUM_ANSWERS; ii++)
		cout << keys[ii]; 
	cout << endl; 
}