#include <stdio.h>
#include <stdlib.h>
#include <conio.h>

typedef struct Student{
	char* studentName; //Dyn. alloc. of stud. name
	long id; // ID Number
	float mark; // mark
	unsigned char subjectStatus;
}Student;

typedef struct University{
	Student* studentArr; // Dync. Alloc(Realloc) of students
	int numOfStudents; //num of students
}University;

void getStudents(University *ptr);
unsigned char stringToBinary(unsigned char tmpSubjectStatus[]);

void main()
{
	printf("Please enter details of student: (a)");
	University uni;
	getStudents(&uni); //Send address of structure University, because we want to change it not make a local copy of it

	getch();
}
void getStudents(University *ptr)
{
	FILE *op;
	char tmpStudentName[20];
	long tmpId;
	float tmpMark;
	char tmpSubjectStatus[6];
	ptr->numOfStudents = 0;
	if ((op = fopen("input.txt", "r")) == NULL)
	{
		printf("Failed to open file.");
	}
	ptr->studentArr = (Student*)malloc(sizeof(Student));
	if (ptr->studentArr == NULL){
		printf("Error: memory was not allocated.");
		exit(1);
	}
	while (fscanf(op, "%s %ld %f %s", tmpStudentName, &tmpId, &tmpMark, tmpSubjectStatus) != NULL)
	{
		ptr->numOfStudents++;
		ptr->studentArr = (Student*)realloc(ptr->studentArr, sizeof(Student) * ptr->numOfStudents); /*Additional code for Realloc fails - we didn't study!*/
		ptr->studentArr[ptr->numOfStudents - 1].studentName = (char*)malloc(sizeof(char)* strlen(tmpStudentName));

		if (!(ptr->studentArr[ptr->numOfStudents - 1].studentName)) //if we failed to allocate memory for studentName
		{
			while (ptr->numOfStudents > 0)
			{
				free(ptr->studentArr[ptr->numOfStudents - 1].studentName); //free  student name
				ptr->numOfStudents--; // decrease numOfStudents by one
			}
			free(ptr->studentArr); //if all student names are free, we need to free the array
			printf("Student name was not allocated.");
			exit(1);
		}

		strcpy(ptr->studentArr[ptr->numOfStudents - 1].studentName, tmpStudentName);
		ptr->studentArr[ptr->numOfStudents - 1].id = tmpId;
		ptr->studentArr[ptr->numOfStudents - 1].mark = tmpMark;
		ptr->studentArr[ptr->numOfStudents - 1].subjectStatus = stringToBinary(tmpSubjectStatus); //atoi: from "11001"(string) to 11001(int),then casting to unsigned char
	}

	fclose(op);
}

unsigned char stringToBinary(char tmpSubjectStatus[])
{
	int tmpInteger;
	int tmpBinary = 0; //convert tmpInteger into binary number
	unsigned char tmpBinaryCh;
	int i = 0;
	int mostRightbit = 16;
	tmpInteger = atoi(tmpSubjectStatus); //Convert from string to int
	while (i < 5){
		if (((16 >> i) & tmpInteger) != 0){
			tmpBinary += (16 >> i);
		}
		i++;
	}
	tmpBinaryCh = (unsigned char)tmpBinary;
	return tmpBinaryCh;
}