///////////////////////////////////////////////////////////
// Softwarebauelemente I, Aufgabe M1.2
//
// author:			Stephan Brumme
// last changes:	October 14, 2000


// include I/O-streams 
#include <iostream.h>


// read all coefficients
int Read(double **arCoefficients)
{
	// store max. exponent
	int nMaxExponent;

	// get max. exponent
	cout<<"Hoechste Potenz: ";
	cin>>nMaxExponent;

	// allocate some memory on the heap
	*arCoefficients = new double[nMaxExponent+1];

	// read all coefficients
	for (int nLoop=nMaxExponent; nLoop>=0; nLoop--)
	{
		cout<<"a"<<nLoop<<": ";
		cin>>(*arCoefficients)[nLoop];
	}

	// return max. exponent
	return nMaxExponent;
}


// calculate correspending Y-value for a given X using Horner formula
double Horner(double dX, int nMaxExponent, double *arCoefficients)
{
	// result, initialize it
	double dResult = 0.0;

	// go thru the whole array and perform Horner
	for (int nLoop = nMaxExponent; nLoop>=0; nLoop--)
	{
		// dResult_new = dResult_old * dX
		dResult *= dX;
		// dResult_new = dResult_old * dX + arCoefficients[nLoop]
		dResult += arCoefficients[nLoop];
	}

	// return result
	return dResult;
}


// main function
void main()
{
	// store coefficients
	double *arCoefficients;
	// get max exponent
	int     nMaxExponent = Read(&arCoefficients);
	// the X value
	double  dX;

	// get X
	cout<<"An welcher Stelle soll der Funktionswert berechnet werden: ";
	cin>>dX;

	// calculate and print Y (using Horner)
	cout<<"f("<<dX<<") = "<<Horner(dX, nMaxExponent, arCoefficients)<<".\n\n";
}