#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

const int NO_OF_QUESTIONS = 20;
 
char examGrade(int score);

int main()
{
    char keyString[NO_OF_QUESTIONS + 1];
    char answerString[NO_OF_QUESTIONS + 1];
    char *ID.ptr;
	ID_ptr = new int[10];

    char ch;

    int score;
    int len;
    ifstream infile;

    int i;

	infile.open("file.txt");
    if (!infile)
    {
        cout << "Cannot open the input file. Program terminates!"
             << endl;
        return 1;
    }

    cout << "Processing Data" << endl;
    infile.get(keyString, 21);

    cout << "Key: " << keyString << endl;
    
    infile >> ID;
    infile.get(ch);
    infile.get(answerString, 21);

    while (infile)
    {
        len = strlen(answerString);
        for (i = len; i < 20; i++)
            answerString[i] = ' ';

        answerString[20] = '\0';
        
        score = 0;
        
        for (i = 0; i < 20; i++)
            if (answerString[i] != ' ')
                if (answerString[i] == keyString[i])
                    score = score + 2;
                else
                    score = score - 1;

        cout << ID << " " << answerString << "  " << score
             << "  " << examGrade(score) << endl;
        infile >> ID;
        infile.get(ch);
    infile.get(answerString, 21);
    }

    cout << endl;

    infile.close();

    return 0;
}

char examGrade(int score)
{
    switch (static_cast<int>(score / 40.0 * 10))
    {
    case 0: 
    case 1: 
    case 2: 
    case 3:
    case 4: 
    case 5: 
        return 'F';
    case 6: 
        return 'D';
    case 7: 
        return 'C';
    case 8: 
        return 'B';
    case 9: 
    case 10: 
        return 'A';
    default: 
        return 'F';
    }
} 

  char *ID.ptr;
	ID_ptr = new int[10];