/*********************************************************
*    This program calculates the Fourier coefficients    *
*   of a periodic function F(x) by using the procedure   *
*   AnalyticFourierHn of unit Fourier.                   *
* ------------------------------------------------------ *
* SAMPLE RUN:                                            *
*                                                        *
* Example 1: F(x) has the following shape:               *
*                                                        *
*  1 ---- 2  pi/4                                        *
*    !  !                                                *
*    !  !                                                *
* ------!-------------------------------------------> x  *
*  -pi  !    0         ! pi                              *
*       !              !                                 *
*     3 ---------------- 4 -pi/4                         *
*                                                        *
* Calculate the Fourier coefficients of a periodic       *
* function F(x):                                         *
*                                                        *
* Begin x of period: -3.1415927                          *
* End of x period: 3.1415927                             *
*                                                        *
* Lowest  harmonic: 0                                    *
* Highest harmonic: 10                                   *
*                                                        *
* a0 = -0.392684481                                      *
* b0 =  0.000000000                                      *
*                                                        *
* a1 = -0.500000000                                      *
* b1 = -0.500029201                                      *
*                                                        *
* a2 = -0.000029201                                      *
* b2 = 0.5000000000                                      *
* -----------------                                      *
* a9 = -0.055555556                                      *
* b9 = -0.055584756                                      *
*                                                        *
* a10 = -0.000029201                                     *
* b10 =  0.100000000                                     *
*                                                        *
* Note that for this kind of sharp angles function, the  *
*      method for discreet functions is far better.      *
*                                                        *
*                                                        *
* Example 2:   F(x) equals 0 from -pi to 0 and sin(x)    *
*              from 0 to pi.                             *
*                                                        *
* Calculate the Fourier coefficients of a periodic       *
* function F(x):                                         *
*                                                        *
* Lowest  harmonic: 0                                    *
* Highest harmonic: 10                                   *
*                                                        *
* a0 =  0.318309886                                      *
* b0 =  0.000000000                                      *
*                                                        *
* a1 =  0.000000012                                      *
* b1 =  0.500000000                                      *
*                                                        *
* a2 = -0.212206591                                      *
* b2 =  0.000000000                                      *
* -----------------                                      *
* a9 = -0.000000000                                      *
* b9 = -0.000000000                                      *
*                                                        *
* a10 = -0.006430503                                     *
* b10 =  0.000000000                                     *
*                                                        *
*                     C++ version by J-P Moreau, Paris.  *
*                           (www.jpmoreau.fr)            *
**********************************************************
(to link with file fourier.cpp).                        */
#include <stdio.h>
#include <math.h>

  void AnalyticFourierHn(double,double,int,double *,double *);


void main()  {

  int count,h1,h2,i;
  double x1,x2, ai,bi;
  char answer[2];

  printf("\n Calculate the Fourier coefficients of a periodic function F(x):\n");
  printf("    (Function F(x) must be defined in file fourier.cpp).\n\n");
  printf(" Begin x of period: "); scanf("%lf", &x1);
  printf(" End x of period  : "); scanf("%lf", &x2);
  printf("\n Lowest  harmonic: "); scanf("%d", &h1);
  printf("\n Highest harmonic: "); scanf("%d", &h2);
  count=1;
  for (i=h1; i<=h2; i++) {
    AnalyticFourierHn(x1,x2,i,&ai,&bi);
    printf("\n  a%d = %12.9f", i, ai);
    printf("\n  b%d = %12.9f\n", i, bi);
    if ((count % 5)==0) {
      count=0;
      scanf("%s", answer);
    }
    count++;
  }
  printf("\n\n");
}

//end of file analfour.cpp