Student Grades

#include <iostream>
#include <fstream>
#include <conio.h>
#include <string>
using namespace std;

struct studentType
{
	string studentFname;
	string studentLname;
	int testScore;
	char grade;
} student[20];
void OpenFile ()
{
	studentType StudentList[20];
	ifstream structFile; //opens struct file
	structFile.open("struct.txt");
	if (structFile.is_open())
	{
		cout << "Student File Opened!   ";
	}
	else cout << "Unable to open struct file. The location may have changed or the file may be damaged.";
}
void assign()
{
	string studentInfo;
	ifstream file("struct.txt"); //assigns grades to students
	if (file.is_open())
	{
		for (int i = 0; i < 20; i++)
		{
			getline(file, studentInfo, ' ');
			student[i].studentFname = studentInfo;
			getline(file, studentInfo, ',');
			student[i].studentLname = studentInfo;
			getline(file, studentInfo, '\n');
			student[i].testScore = stoi(studentInfo);

		}
	}
	else cout << "Unable to open struct file. The location may have changed or the file may be damaged.";
	cout << "Grades Assigned!   "; //displays only if grades are assigned to students
}
void grade()
{
	for (int i = 0; i < 20; i++) //assignes letter grades to number
	{
		if (student[i].testScore < 60)
		{
			student[i].grade = 'F'; //bad grade
		}
		else if (student[i].testScore < 70)
		{
			student[i].grade = 'D';
		}
		else if (student[i].testScore < 80)
		{
			student[i].grade = 'C';
		}
		else if (student[i].testScore < 90)
		{
			student[i].grade = 'B';
		}
		else if (student[i].grade = 'A');
	}
	cout << "Letters assigned!\n\n"; //displays only if letters are assigned to grade
}
void DisplayStudents()
{
	cout << "Last Name, First Name\t Grade" << "\n";
	cout << "\nStudents: \n";
	int highest = 0;
	int spaces;
	for (int i = 0; i < 20; i++)
	{
		if (student[i].studentFname.size() + student[i].studentLname.size() > highest)
		{
			highest = student[i].studentFname.size() + student[i].studentLname.size();
		}
	}
	for (int i = 0; i < 20; i++)
	{
		spaces = (highest - (student[i].studentFname.size() + student[i].studentLname.size()) + 2);
		cout << "\n" << student[i].studentLname << ", " << student[i].studentFname;
		for (int i = 0; i < spaces; i++)
		{
			cout << " ";
		}
		cout << student[i].grade << " - " << student[i].testScore;
	}
	cout << "\n\n";
}
int main() //man function
{
	OpenFile();
	assign();
	grade();
	DisplayStudents();
	system("PAUSE");
	return 0;
}