HW1 MATAM

#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<conio.h>
#include<math.h>
/*structions decleration*/
typedef struct Student
{
    char *name;
    long id;
    int exam_grade;
    char program;
    char labs[5];
    char hw_grade;
}Student;

typedef struct University
{
    Student *arr;
    int amount;
}University;

/*functions decleration*/
void Error_Msg(char* str);
void input_university(FILE *input, University* un);
void output_university(FILE *output, University* un);
void hw_grades(University* un);
void final_grade(FILE *output, University* un);
void uni_stats(FILE *output, University* un);
void above_avg(FILE *output, University* un);

void main()
{
    University Braude;
    FILE *input, *output;
    int option, i;

    Braude.arr = (Student*)malloc(sizeof(Student));

    if (Braude.arr == NULL)
        Error_Msg("Allocation failed");
    /* initializing "input" to point to the txt file we created, as well as checking for faliure*/
    if (!(input = fopen("input.txt", "r")))
        Error_Msg("Error searching for file");

    printf("Enter option (1-6), You must start with option 1: ");
    scanf("%d", &option);
    while (option != 1)
    {
        printf("You must start with option 1, try again: ");
        scanf("%d", &option);
    }
    while (option!=6)
    {
        /* Creating a new empty txt file called "output" /writing over the last one*/
        if (!(output = fopen("output.txt", "w")))
            Error_Msg("Error! unable to create file");
        switch (option)
        {
        case 1:
            input_university(input, &Braude);
            hw_grades(&Braude);
            break;
        case 2:
            output_university(output, &Braude);
            break;
        case 3:
            final_grade(output, &Braude);
            break;
        case 4:
            uni_stats(output, &Braude);
            break;
        case 5:;
            above_avg(output, &Braude);
            break;
        default:
            printf("Error, Wrong input\n ");
        }
        fclose(output);
        printf("What would you like to do next? (2-6): ");
        scanf("%d", &option);
    }
    if (!(output = fopen("output.txt", "w")))
        Error_Msg("Error! unable to create file");

    fprintf(output, "%s", "End Of Program");
    printf("\nGood Bye!\n");
    /*Closing files*/
    fclose(output);
    fclose(input);

    for (i = 0; i < Braude.amount; i++)
        free(Braude.arr[i].name);
    free(Braude.arr);

    getch();
}

void Error_Msg(char* str)
{
    printf("\n%s", str);
    exit(1);
}

void input_university(FILE *input, University* un)
{
    int i = 0;
    char tmp_name[99];
    char tmp_labs[6];
    while (fscanf(input, "%s %ld %d %s %c", tmp_name, &un->arr[i].id, &un->arr[i].exam_grade, tmp_labs, &un->arr[i].program) != EOF)
    {
        un->arr[i].name = (char*)malloc((strlen(tmp_name) + 1)*sizeof(char));
        if (un->arr[i].name == NULL)
            Error_Msg("Allocation failed");
        strcpy(un->arr[i].name, tmp_name);
        strcpy(un->arr[i].labs, tmp_labs);
        i++;
        un->arr = (Student*)realloc(un->arr, (i+1)*sizeof(Student));
        if (un->arr == NULL)
            Error_Msg("Allocation failed");
    }
    un->amount = i;
}

void hw_grades(University* un)
{
    int i,j;
    for (i = 0; i < un->amount; i++)
    {
        int cnt = 0;
        for (j = 0; j < 5; j++)
            if (un->arr[i].labs[j] == '1')
                cnt++;
        if (cnt>2)
            un->arr[i].hw_grade = '1';
        else
            un->arr[i].hw_grade = '0';
    }

}

void output_university(FILE *output, University* un)
{
    int i;
    for (i = 0; i < un->amount; i++)
    {
        fprintf(output,"Student %d: %s ", i + 1, un->arr[i].name);
        fprintf(output, "%ld %d ", un->arr[i].id, un->arr[i].exam_grade);
        fprintf(output, "%c %c\n", un->arr[i].hw_grade, un->arr[i].program);
    }
}

void final_grade(FILE *output, University* un)
{
    int i;
    fprintf(output, "BEFORE:\n");
    output_university(output, un);
    fprintf(output, "\nATFER:\n");
    for (i = 0; i < un->amount; i++)
    {
        if (un->arr[i].exam_grade>54)
        if (un->arr[i].hw_grade == '1')
        if (un->arr[i].program == 'Y')
            un->arr[i].exam_grade = (float)un->arr[i].exam_grade*0.8 + 20;
        else
            un->arr[i].exam_grade = (float)un->arr[i].exam_grade*0.9 + 10;
    }
    output_university(output, un);
}

void uni_stats(FILE *output, University* un)
{
    float avg=0,sd=0;
    int i, min=100, max=0,old=0,new=0;

    /*Average calculation*/
    for (i = 0; i < un->amount; i++)
        avg += un->arr[i].exam_grade;
    avg /= un->amount;

    /*Standard Deviation, Range, program calculation*/
    for (i = 0; i < un->amount; i++)
    {
        sd += pow(((double)un->arr[i].exam_grade - avg), 2);
        if (un->arr[i].exam_grade>max)
            max = un->arr[i].exam_grade;
        if (un->arr[i].exam_grade < min)
            min = un->arr[i].exam_grade;
        if (un->arr[i].program == 'Y')
            new++;
        else
            old++;
    }
    sd /= un->amount;
    sd = sqrt((double)sd);

    fprintf(output, "Average: %g\n", avg);
    fprintf(output, "Standard Deviation: %g\n", sd);
    fprintf(output, "Student amount: %d\n", un->amount);
    fprintf(output, "Range: %d - %d\n", max,min);
    fprintf(output, "New program: %d\n", new);
    fprintf(output, "Old program: %d", old);
}

void above_avg(FILE *output, University* un)
{
    char prog;
    int i;
    float avg=0;
    /*Average calculation*/
    for (i = 0; i < un->amount; i++)
        avg += un->arr[i].exam_grade;
    avg /= un->amount;
    /*Program Choise*/
    printf("Which program would you like to view? (Y/N): ");
    flushall();
    scanf("%c", &prog);
    /*Input Check*/
    while (prog != 'Y' &&prog != 'N')
    {
        printf("Error, please enter \'Y\' OR \'N\':");
        flushall();
        scanf("%c", &prog);
    }
    for (i = 0; i < un->amount; i++)
    {
        if (un->arr[i].program == prog)
        {
            if (un->arr[i].exam_grade>avg)
            {
                fprintf(output, "Student %d: %s ", i + 1, un->arr[i].name);
                fprintf(output, "%ld %d ", un->arr[i].id, un->arr[i].exam_grade);
                fprintf(output, "%c %c\n", un->arr[i].hw_grade, un->arr[i].program);
            }
        }
    }
}