last c++

#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <cstring>
#define SIZE 30
using namespace std;

typedef struct
{
	char name[31];
	int grade1;
	int grade2;
	double average;
} STUDENTREC;

int read_grade(STUDENTREC stud_arr[], int index);
void list(const STUDENTREC stud_arr[], int size);

int main(void)
{
	int action, index = 0;
	bool quit = false;
	STUDENTREC students[SIZE];

	while(!quit)
	{
		cout <<"\n\t\t******************************************";
		cout <<"\n\t\t**\tStudent Records Menu\t\t**";
		cout <<"\n\t\t******************************************\n\n";
		cout <<"\t\t<1> Read Grade.\n";
		cout <<"\t\t<2> List.\n";
		cout <<"\t\t<3> Quit.\n\n";
		cout <<"\tPlease enter your option --> ";
		cin >> action;
		cout <<"\n\n";

		if(action == 1)
			index = read_grade(students, index);
		else if(action == 2)
			list(students, index);
		else if(action == 3)
			quit = true;
		else
			cout <<"\tWrong selection.\n";
	}
}

int read_grade(STUDENTREC stud_arr[], int index)
{
	if(index >= SIZE)
		cout << "Array is full.\n";
	else
	{
		cout <<"\tPlease enter the student name : ";
		fflush(stdin);
		cin.get(stud_arr[index].name, 31);
		cout <<"\tPlease enter the student grade 1: ";
		cin >> stud_arr[index].grade1;
		cout <<"\tPlease enter the student grade 2: ";
		cin >> stud_arr[index].grade2;
		stud_arr[index].average = (double)(stud_arr[index].grade1 + stud_arr[index].grade2) / 2.0;
		cout <<"\tThe average of the student grades is "
		     << fixed << setprecision(2) << stud_arr[index].average << endl;
		index++;
	}
	return index;
}

void list(const STUDENTREC stud_arr[], int size)
{
	if(size <= 0)
	{
		cout << "\tNo record.\n";
		return;
	}

	cout <<"Name\t\t\tGrade1\t\tGrade2\t\tAverage\n";
	for(int i = 0; i < size; i++)
	{
		if (strlen(stud_arr[i].name) < 15)
			cout << stud_arr[i].name << "\t\t"
			     << setw(3) << stud_arr[i].grade1 << "\t\t"
			     << setw(3) << stud_arr[i].grade2 << "\t\t"
			     << setw(6) << fixed << setprecision(2)
			     << stud_arr[i].average << endl;
		else
			cout << stud_arr[i].name << "\t"
			     << setw(3) << stud_arr[i].grade1 << "\t\t"
			     << setw(3) << stud_arr[i].grade2 << "\t\t"
			     << setw(6) << fixed << setprecision(2)
			     << stud_arr[i].average << endl;
	}
}