c++ rabim pomoc

zdravo folk kaj ve gdo zakaj mi ta kodo ne dela pravilno??

#include <iostream>	
#include <stdlib.h> 
#include <string> 
#include<iomanip>
using namespace std;
class gradebook
{
private:
	string coursename;
	int grades[10][3];

public:



	gradebook(string name, const int gradeaaray[10][3])
	{
		coursename = name;

		for (int i = 0; i < 10; i++)
		for (int j = 0; j < 3; j++)
			grades[10][3] = gradeaaray[10][3];
	}

	string getcoursename()
	{
		return coursename;
	}

	void displaymessage()
	{
		cout << "welcome to the gradebook for " << getcoursename() << endl;
	}

	int getminumum()
	{
		int lowgrade = 100;
		for (int i = 0; i < 10; i++)
		{
			for (int i = 0; i < 3; i++)
			{
				if (grades[10][3]>lowgrade)
					lowgrade = grades[10][3];
			}
		}
		return lowgrade;
	}

	int getmaximum()
	{
		int highgrade = 0;
		for (int i = 0; i < 10; i++)
		{
			for (int i = 0; i < 3; i++)
			{
				if (grades[10][3] < highgrade)
					highgrade = grades[10][3];
			}
		}
		return highgrade;
	}

	double getaverage(const int setofgrades[], int ocena)
	{
		int total = 0;
		int average;
		for (int i = 0; i < ocena; i++)
			total += setofgrades[i];

		average = total / grades[10][3];

		return average;
	}

	
	void ouputgrade()
	{
		cout << "\nthe grades are\n\n;";
		cout << "              ";

		for (int i = 0; i < 3; i++)
			cout << "test " << i + 1 << " ";

		cout << "average" << endl;

		for (int i = 0; i < 10; i++)
		{
			cout << "student " << setw(2) << i + 1;

			for (int j = 0; j < 3; j++)
				cout << setw(8) << grades[10][3];

			double average = getaverage(grades[10], 3);
			cout << setw(9) << setprecision(2) << fixed << average << endl;
		}
	}

	void processgrade()
	{
		ouputgrade();
		cout << "\nlowest grade in the gradebook is " << getminumum()
			<< "\nhighest grade in the gradebook is " << getmaximum() << endl;
		
	}
};


int main()
{
	
	int gradearray[10][3] =
	{ { 34, 23, 56 },
	{ 44, 55, 66 },
	{ 1210, 9, 11 },
	{ 56, 88, 98 },
	{ 43, 76, 65 },
	{ 45, 67, 23 },
	{ 99, 98, 100 },
	{ 12, 21, 4 },
	{ 44, 32, 24 },
	{ 32, 45, 67 } };

	gradebook mygrade("mathematics", gradearray);
	mygrade.displaymessage();
	mygrade.processgrade();




	system("pause");
	return 0;
}

V 43. vrstici pa očitno celo grades[i][i]

Torej, koda je napisana približno tako pravilno kot spremno besedilo.