// Trying.cpp : Calculates determinant of a matrix, either

// 2x2 or 3x3


#include "stdafx.h"
#include <iostream>

double twoByTwo();
double threeByThree();

bool quit = false;

int main(int argc, char* argv[])
{
	bool done = false;  //quit loop and variable.  If false, program will continue to run

	while (done == false)
	{
		using namespace std;
		//making menu

		cout << "               ***MAIN MENU***";
		cout << "\n  (1)Calculate a two by two determinant";
		cout << "\n  (2)Calculate a three by three determinant";
		cout << "\n  (3)Quit\n";
		int menuChoice; //choice from menu

		cin >> menuChoice;
		double detd;
		switch (menuChoice)//Going to specialized functions or quitting

		{
			case 1:		
				detd = twoByTwo();
				cout << "The determinant is equal to: " << detd << "\n\n";
				break;
			case 2:		
				detd = threeByThree();
				cout << "The determinant is equal to: " << detd << "\n\n";
				break;
			case 3:		
				char exit;
				do
				{
					cout << "Are you sure you want to quit?  Y for yes or N for no:\n";
					cin >> exit;
					switch (exit)
					{
					case 'y':
					case 'Y':
						done = true;
						quit = true;
						break;
					case 'n':
					case 'N':
						done = false;
						quit = true;
						break;
					default:
						cout << "Enter y or n to exit.\n";
						break;
					}
				} while (quit == false);
				break;
			default:	
				cout << "Try again, please.\n\n";
				break;
		}
	}
		return 0;
}


double twoByTwo{
	using namespace std;
	float determinant[2][2];
	cout << "n[x][y] represents the x row and the y column.\n";
	for (int i=0; i<2; i++)
	{
		for (int j=0; j<2; j++)
		{
			cout << "Enter n[" << i+1 << "][" << j+1 << "]:  ";
			cin >> determinant[i][j];
		}
	}
	cout << endl << "The determinant that you entered is:" << endl;
	for (i=0; i<2; i++)
	{
		for (int j=0; j<2; j++)
		{
			cout << determinant[i][j];
			cout << "\t";
		}
		cout << endl;
	}
	cout << endl << endl;
	double det = (determinant[0][0]*determinant[1][1])-(determinant[0][1]*determinant[1][0]);
	return det;
}

double threeByThree()//to calculate determinant of a three by three

{
	using namespace std;
	float determinant[3][3];
	cout << "n[x][y] represents the x row and the y column.\n";
	for (int i=0; i<3; i++)
	{
		for (int j=0; j<3; j++)
		{
			cout << "Enter n[" << i+1 << "][" << j+1 << "]:  ";
			cin >> determinant[i][j];
		}
	}
	cout << endl << "The determinant that you entered is:" << endl;
	for (i=0; i<3; i++)
	{
		for (int j=0; j<3; j++)
		{
			cout << determinant[i][j];
			cout << "\t";
		}
		cout << endl;
	}
	cout << endl << endl;
	double det = ((determinant[0][0]*determinant[1][1]*determinant[2][2])
+(determinant[0][1]*determinant[1][2]*determinant[2][0])
+(determinant[0][2]*determinant[1][0]*determinant[2][1]))
-((determinant[0][2]*determinant[1][1]*determinant[2][0])
+(determinant[0][1]*determinant[1][0]*determinant[2][2])
+(determinant[0][0]*determinant[1][2]*determinant[2][1]));
	return det;
}