// Name: Julians Krumins
// Date: February 26, 2020
// Project: ECE_Exercise_21

#include<iostream>
#include<cstdlib>
using namespace std;


void new_random_array(double a[], int s)
{
	for (int n=0; n < s; n++)
	{
		a[n] = double(rand() % 100);
	}
}

void display_array(double a[], int s)
{
	for (int n = 0; n < s; n++)
	{
		cout << a[n] << endl;
	}
}

double array_max(double a[], int s)
{
	double max = a[0];
	for (int n = 1; n < s; n++)
	{
		if (a[n] > max)
		{
			max = a[n];
		}
	}
	return max;
}

double array_min(double a[], int s)
{
	double min = a[0];
	for (int n = 1; n < s; n++)
	{
		if (a[n] < min)
		{
			min = a[n];
		}
	}
	return min;
}

void array_sort(double a[], int s)
{
	double swap = 0;
	for (int i = s - 1; i > 0; i--)
	{
		for (int j = 0; j < i; j++)
		{
			if (a[j] < a[j + 1])
			{
				swap = a[j];
				a[j] = a[j + 1];
				a[j + 1] = swap;
			}
		}
	}
	return;
}
void array_disp(double a[], int s)
{
	array_sort(a, s);
	for (int i = 0; i < s; i++)
	{
		cout << a[i] << " " << endl;
	}
	cout << endl;
}

double array_mean(double a[], int s)
{
	double sum = 0;
	for (int n = 0; n < s; n++)
	{
		sum = sum + a[n];
	}
	return sum / s;
}

double array_median(double a[], int s)
{
	double med = 0;
	array_sort(a, s);
		if (s % 2 == 1)
		{
			med = a[s / 2];
		}
		else
		{
			med = (a[s / 2] + a[s / 2 - 1]) / 2.0;
		}
		return med;
}
double array_variance(double a[], int s)
{
	double mean = array_mean(a, s);
	double var = 0;
	for (int n = 0; n < s; n++)
	{
		var = var + (a[n] - mean) * (a[n] - mean);
	}
	var = var / (double(s) - 1);
	return var;
}

int main()
{
	const int size = 10;
	double array[size];
	int selection = 0;

	do
	{
		system("cls");

		cout << "Main Menu" << endl;
		cout << "1. Create a new array" << endl;
		cout << "2. Display array" << endl;
		cout << "3. Find Maximum value" << endl;
		cout << "4. Find Minimum value" << endl;
		cout << "5. Sort the array in descending order and display" << endl;
		cout << "6. Find mean value" << endl;
		cout << "7. Find median value" << endl;
		cout << "8. Find variance" << endl;
		cout << "9. End." << endl << endl;
		cout << "Make a selection: ";
		cin >> selection;

		switch (selection)
		{
		case 1:
			cout << "Created array. " << endl;
			new_random_array(array, size);
			cout << endl;
			system("pause");
			break;
		case 2:
			cout << "Display array: " << endl;
			display_array(array, size);
			cout << endl;
			system("pause");
			break;
		case 3:
			cout << "Maximum value: ";
			cout << array_max(array, size);
			cout << endl;
			system("pause");
			break;
		case 4:
			cout << "Minimum value: ";
			cout << array_min(array, size);
			cout << endl;
			system("pause");
			break;
		case 5:
			cout << "5. Sorted in descending order: " << endl;
			array_disp(array, size);
			cout << endl;
			system("pause");
			break;
		case 6:
			cout << "mean value: ";
			cout << array_mean(array, size);
			cout << endl;
			system("pause");
			break;
		case 7:
			cout << "median value: ";
			cout << array_mean(array, size);
			cout << endl;
			system("pause");
			break;
		case 8:
			cout << "variance: ";
			cout << array_variance(array, size);
			cout << endl;
			system("pause");
			break;
		case 9:
			break;
			system("cls");
		}
	} while (selection != 0);
	return 0;
}