Question

The history teacher at your school needs help in grading a True/False test. The students’ IDs and test answers are stored in a file. The first entry in the file contains answers to the test in the form: TFFTFFTTTTFFTFTFTFTT
Every other entry in the file is the student ID, followed by a blank, followed by the student’s responses. For example, the entry:
ABC54301 TFTFTFTT TFTFTFFTTFT
indicates that the student ID is ABC54301 and the answer to question 1 is True, the answer to question 2 is False, and so on. This student did not answer question 9. The exam has 20 questions, and the class has more than 150 students. Each correct answer is awarded two points, wrong answer gets one point deducted, no answer gets zero points. Write a program that processes the test data. The output should be the student’s ID, followed by the answers, followed by the test score, followed by the test grade. Assume the following grade scale: 90%–100%, A; 80%–89.99%, B; 70%–79.99%, C; 60%–69.99%, D; and 0%–59.99%, F. use dynamic arrays

Answer 1

Answer on Question #48489 – Programming - C

#include <stdio.h>
#include <stdlib.h>
typedef struct {
    char name[20];
    char answer[21];
    int score;
    char grade;
} student;
int main() {
    student **array = NULL, **temp_array = NULL;
    student *curr_stud = NULL;
    FILE* file;
    char filename[200];
    char answer[20];
    double grade;
    int i, students_count = 0, array_size = 0;
    char result = 0;
    while (true) {
        printf("Enter filename: ");
        scanf("%s", filename);
        file = fopen(filename, "r");
        if (file == NULL) {
            printf("Error opening file!\n");
        } else {
            break;
        }
    }
    for (i = 0; i < 20; i++) {
        fscanf(file, "%c", answer + i);
    }
    while (feof(file) == 0) {
        if (students_count == array_size) {
            array_size += 5;
            temp_array = (student**)malloc(array_size * sizeof(student*));
            for (i = 0; i < students_count; i++) {
                temp_array[i] = array[i];
            }
            free(array);
            array = temp_array;
        }
        curr_stud = (student*)malloc(sizeof(student));
        if (fscanf(file, "%s", curr_stud->name) < 1) break;
        else {
            curr_stud->score = 0;
            fgetc(file);
            for (i = 0; i < 20; i++) {
                curr_stud->answer[i] = fgetc(file);
                if (curr_stud->answer[i] != ' ') {
                    if (curr_stud->answer[i] == answer[i])
                        curr_stud->score += 2;
                    else
                        curr_stud->score -= 1;
                }
            }
            curr_stud->answer[20] = '\0';
            grade = curr_stud->score / (20 * 2.0);
            if (grade >= 0.9) curr_stud->grade = 'A';
            else if (grade >= 0.8) curr_stud->grade = 'B';
            else if (grade >= 0.7) curr_stud->grade = 'C';
            else if (grade >= 0.6) curr_stud->grade = 'D';
            else curr_stud->grade = 'F';
            array[students_count++] = curr_stud;
        }
    }
    fclose(file);
    for (i = 0; i < students_count; i++) {
        printf("%s - %s - %d - %c\n", array[i]->name, array[i]->answer, array[i]->score, array[i]->grade);
    }
    printf("Save result? (y\n) ");
    getchar();
    scanf("%c", &result);
    if (result == 'y' || result == 'Y') {
        while (true) {
            printf("Enter filename: ");
            scanf("%s", filename);
            file = fopen(filename, "w+");
            if (file == NULL) {
                printf("Error opening file!\n");
            } else {
                break;
            }
            for (i = 0; i < students_count; i++) {
                fprintf(file, "%s - %s - %d - %c\n", array[i]->name, array[i]->answer, array[i]->score, array[i]->grade);
            }
            fclose(file);
        }
        for (i = 0; i < students_count; i++) {
            free(array[i]);
        }
        free(array);
    }
}

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