Easy Program: Store Data from a file into a Struct Array - c++

Question

I am new to programming and I am having trouble reading data from a file and entering it into a struct array, while keeping track of each data being entered:
The file would contain:
Name, ID Number, and GPA
Courtney Love 1234569 3.5
Bob Joe 1234570 3.0
Dave Henry 1234571 2.9
struct Student
{
string name;
int id;
float GPA;
void printStudent();
};
Declare an array of Student type that can hold up to 5 members:
Student a_members[5];
Open the file, read in each line and store the data in the array, keep track of each student read in:
fstream file_;
file_.open ("students.txt");
if(file_.is_open())
{
while(file_.good())
{
}
}
else
{
cout << "File is not open"<< endl;
}
return 0;
I am stuck on the "while" conditional statement. After that I don't know what I should do to input the data from the file line by line and place into the "struct array". As of right now, I feel like I have tried everything! I deleted everything and figured it was best to start over. It was becoming too complicated! Maybe I am just not understanding the concept. If anyone can point me in the right direction, please do so! Thank you!

Answer 1

You should not use good(), just like you should not use eof().
(Neither is used in any decent beginner-level material, yet every beginner manages to find them. And then they wonder why it didn't work.)
You should instead rely on the fact that a stream itself is "true-ish" if it's in a good state, and just keep reading until it isn't.
Idiomatic C++ would look like this:
std::ifstream file("students.txt");
Student s;
while (file >> s.name >> s.id >> s.GPA)
{
// Process the student
}
or, a fancy version:
std::istream& operator>> (std::istream& is, Student& s)
{
return is >> s.name >> s.id >> s.GPA;
}
std::ifstream file("students.txt");
Student s;
while (file >> s)
{
// Process the student
}
(In your code, you'll need to also keep track of how many Students you've read.)

Answer 2

Here is one from possible solutions:
#include <iostream>
#include <vector>
#include <fstream>
struct Student
{
Student() : first_name(), surname(){}
char first_name[64];
char surname[64];
int id;
float GPA;
void printStudent()
{
std::cout << "Name: " << first_name << " " << surname << " ID: " << id << " GPA: " << this->GPA << std::endl;
}
};
std::vector<Student>student;
bool LoadFile(const char* filename)
{
if (filename == NULL)return false;
std::fstream stream(filename, std::ios::in);
if (!stream.is_open())return false;
else
{
char buffer[255]; // for solution 1!
while (!stream.eof())
{
memset(buffer, 0, sizeof(buffer));
Student _student;
#pragma region SOLUTION_1
//stream.getline(buffer, sizeof(buffer));
//sscanf(buffer, "%s %s %d %f", _student.first_name, _student.surname, &_student.id, &_student.GPA);
#pragma endregion
#pragma region SOLUTION_2
stream >> _student.first_name >> _student.surname >> _student.id >>_student.GPA;
#pragma endregion
student.push_back(_student);
student[student.size() - 1].printStudent();
}
}
return true;
}
int main()
{
LoadFile("students.txt");
getchar();
return 0;
}