/*
 *  ==============================================================
 *  Evaluation of         f(x) = 2 + 3.x + 4.x^2 + 5.x^3 + 6.x^4
 *  using Horner's Rule        = 2 + x.(3. + x.(4 + x.(5. + 6.x)))
 * 
 *  Copyright (C) 1998 by Mark Austin and David Chancogne.
 *                                                                     
 *  This software is provided "as is" without express or implied warranty.
 *  Permission is granted to use this software on any computer system,
 *  and to redistribute it freely, subject to the following restrictions:
 * 
 *  1. The authors are not responsible for the consequences of use of
 *     this software, even if they arise from defects in the software.
 *  2. The origin of this software must not be misrepresented, either
 *     by explicit claim or by omission.
 *  3. Altered versions must be plainly marked as such, and must not
 *     be misrepresented as being the original software.
 *  4. This notice is to remain intact.
 * 
 *  Written By : Mark Austin
 *  ==============================================================
 */

#include <stdio.h>

int main( void ) {
  float fA = 2.0F;
  float fB = 3.0F;
  float fC = 4.0F;
  float fD = 5.0F;
  float fE = 6.0F;
  float fX1;

/* [a] : Prompt user for value of function variable */

   printf("Please enter coefficient fX : ");
   fflush(stdout)
   scanf("%f%*c", &fX);

/* [b] : Evaluate polynomial as sum of product terms */

   fX1 = fA + fB*fX + fC*fX*fX + fD*fX*fX*fX + fE*fX*fX*fX*fX;
   printf("Sum of Product terms       : F(%4.2f) = %4.2f\n", fX ,fX1 );

/* [c] : Evaluate polynomial using Horner's Rule */

   fX1 = fA + fX*(fB + fX*(fC + fX*(fD + fX*fE)));
   printf("Using Horner's Rule        : F(%4.2f) = %4.2f\n", fX ,fX1 );
}