/*******************************************************
*      Program to demonstrate synthetic division       *
*              of polynomials subroutine               *
* ---------------------------------------------------- *
*   Reference: BASIC Scientific Subroutines, Vol. II   *
*   By F.R. Ruckdeschel, BYTE/McGRAWW-HILL, 1981 [1].  *
*                                                      *
*                  C++ version by J-P Moreau, Paris.   *
*                         (www.jpmoreau.fr)            *
* ---------------------------------------------------- *
* SAMPLE RUN:                                          *
* ( Example: Divide (x+1)^5 by (x+1) )                 *
*                                                      *
*         DIVISION OF POLYNOMIALS                      *
*                                                      *
* What is the degree of the first polynomial: 5        *
*                                                      *
* Input the first polynomial coefficients as prompted: *
*                                                      *
*   C( 0) = 1                                          *
*   C( 1) = 5                                          *
*   C( 2) = 10                                         *
*   C( 3) = 10                                         *
*   C( 4) = 5                                          *
*   C( 5) = 1                                          *
*                                                      *
* What is the degree of the second polynomial: 1       *
*                                                      *
* Input the second polynomial coefficients as prompted:*
*                                                      *
*   B( 0) = 1                                          *
*   B( 1) = 1                                          *
*                                                      *
* The coefficients of the resulting polynomial are:    *
*                                                      *
*   A( 0) = 1.000000                                   *
*   A( 1) = 4.000000                                   *
*   A( 2) = 6.000000                                   *
*   A( 3) = 4.000000                                   *
*   A( 4) = 1.000000                                   *
*                                                      *
*******************************************************/
#include <stdio.h>
#include <math.h>

#define  SIZE  25

int     i,n1,n2;
double  A[SIZE], B[SIZE], C[SIZE];


/***********************************************
* Synthetic Division of polynomials Subroutine *
* -------------------------------------------- *
* It is assumed that polynomial coefficients   *
* are real.  Calculates A(x)=C(x)/B(x).        *
* C(x) is of order n1,  B(x) is of order n2,   *
* A(x) is at most of order n1-n2 (n1>n2).      *
***********************************************/
void Division()  { 
  //Label e100
  int i,j;
  for (i=n1; i>n2-1; i--) {
   A[i-n2]=C[i]/B[n2];
   if (i==n2) goto e100;
   for (j=0; j<n2+1; j++)
     C[i-j]=C[i-j]-A[i-n2]*B[n2-j];
e100: ; }
}


void main()  {
  printf("\n         DIVISION OF POLYNOMIALS\n\n");
  printf(" What is the degree of the first polynomial: ");
  scanf("%d",&n1);
  printf("\n Input the first polynomial coefficients as prompted:\n\n");
  for (i=0; i<n1+1; i++) {
    printf("   C(%d) = ",i); scanf("%lf",&C[i]);
  }
  printf("\n What is the degree of the second polynomial: "); 
  scanf("%d",&n2);
  printf("\n Input the second polynomial coefficients as prompted:\n\n");
  for (i=0; i<n2+1; i++) {
    printf("   B(%d) = ",i); scanf("%lf",&B[i]);
  };
  
  Division();

  printf("\n\n The coefficients of the resulting polynomial are:\n\n");
  for (i=0; i<n1-n2+1; i++)
    printf("   A(%d) = %f\n",i,A[i]);
  printf("\n");
}

// End of file rsyndiv.cpp