///////////////////////////////////////////////////////////
// Softwarebauelemente I, Aufgabe M1.1
//
// author:			Stephan Brumme
// last changes:	October 14, 2000


// include I/O-streams and math library (we use sin())
#include <iostream.h>
#include <math.h>

// define pi (11 digits should be enough)
const double pi = 3.1415926535;


// calculate the area of a n-angled surface
void AreaNEdges()
{
	// amount of edges
	unsigned int nEdges;
	// radius
	double dRadius;
	// surface area
	double dArea;

	// read edges
	cout<<"Ecken: ";
	cin>>nEdges;

	// read radius
	cout<<"Umkreisradius: ";
	cin>>dRadius;

	// calculate surface area using the given formula
	dArea = (double)nEdges*0.5 * dRadius*dRadius * sin(2*pi/(double)nEdges);

	// print result
	cout<<"Ein "<<nEdges<<"-Eck mit einem Umkreisradius von "<<dRadius
		<<" hat einen Flaecheninhalt von "<<dArea<<".\n\n";
}


// calculate the volume of a cone stub
void VolumeConeStub()
{
	// height of the stub
	double dHeight;
	// radius'
	double dRadius1;
	double dRadius2;
	// volume
	double dVolume;

	// get height
	cout<<"Height of the cone stub: ";
	cin>>dHeight;

	// get both radius'
	cout<<"Radius 1: ";
	cin>>dRadius1;
	cout<<"Radius 2: ";
	cin>>dRadius2;

	// calculate volume using the given formula
	dVolume = (pi*dHeight/3.0) * (dRadius1*dRadius1 + dRadius1*dRadius2 + dRadius2*dRadius2);

	// print result
	cout<<"Ein gerader Kreiskegelstumpf der Hoehe "<<dHeight<<" mit den Radien "<<dRadius1
		<<" und "<<dRadius2<<" hat ein Volumen von "<<dVolume<<".\n\n";
}


// calculate the arithmetic average of a data set
void ArithmeticAverage()
{
	// size of data set
	unsigned int nAmount;
	// data set
	double *arData;
	// result
	double  dAverage;

	// get size of data set
	cout<<"Von wievielen Zahlen soll das arithmetische Mittel berechnet werden: ";
	cin>>nAmount;

	// allocate memory on heap to store the data set
	arData = new double[nAmount];

	// read data set
	for (unsigned int nLoop=0; nLoop<nAmount; nLoop++)
	{
		cout<<"Wert "<<nLoop+1<<": ";
		cin>>arData[nLoop];
	}

	// sum up the data
	dAverage = 0;
	for (nLoop=0; nLoop<nAmount; nLoop++)
		dAverage += arData[nLoop];
	// divide by size of data set
	dAverage /= nAmount;

	// print result
	cout<<"Das arithmetische Mittel dieser Werte ist "<<dAverage<<".\n\n";	
}


// main function
void main()
{
	AreaNEdges();
	VolumeConeStub();
	ArithmeticAverage();
}