/**************************************************************
*     Analyze a real function F(x) by giving its equation     *
* ----------------------------------------------------------- *
* Ref.: Analyse numérique en C By Alain Reverchon and         *
*       Marc Ducamp, Armand Colin Editor, Paris, 1990"        *
*       [BIBLI 14].                                           *
* ----------------------------------------------------------- *
* SAMPLE RUN:                                                 *
*                                                             *
*                                                             *
* Analyze a real function F(x) by giving its equation         *
*                                                             *
* Enter equation of Function f(x): sin(x)/x                   *
*                                                             *
*  Begin x: 0.1                                               *
*                                                             *
*  End x  : 1                                                 *
*                                                             *
*  Number of points: 10                                       *
*                                                             *
*  Caption: SIN(X)/X                                          *
*                                                             *
*                                                             *
* SIN(X)/X                                                    *
*                                                             *
* x=      0.100000000000  y=      0.998334166468  # 1798/1801 *
* x=      0.200000000000  y=      0.993346653975  # 1493/1503 *
* x=      0.300000000000  y=      0.985067355538  # 2045/2076 *
* x=      0.400000000000  y=      0.973545855772  # 5741/5897 *
* x=      0.500000000000  y=      0.958851077200  # 4707/4909 *
* x=      0.600000000000  y=      0.941070788992  # 2619/2783 *
* x=      0.700000000000  y=      0.920310981768  # 947/1029  *
* x=      0.800000000000  y=      0.896695113624  # 4097/4569 *
* x=      0.900000000000  y=      0.870363232919  # 2276/2615 *
* x=      1.000000000000  y=      0.841470984808  # 2723/3236 *
*                                                             *
* (In this version, we only display the calculated couples    *
*  [xi,yi]). See API demo program grfunct1.cpp to have a      *
*  graph of the analyzed function.                            *  
*                                                             *
*                           C++ version by J-P Moreau, Paris. *
*                                 (www.jpmoreau.fr)           *
* ----------------------------------------------------------- *
* Note: this program demonstrates the capability of the module*
*       Fonction.cpp to compile a user defined real function  *
*       F(x), given by its equation, and to evaluate a current*
*       point.                                                *
*                                                             *
* Accepted signs and operators:                               *
* ----------------------------                                *
* 0,1,2,3,4,5,6,7,8,9,(,),-,+,*,/,^,SIN,COS,TAN,ARCSIN,ARCCOS,*
* ARCTAN,SH,CH,TH,ARGSH,ARGCH,ARGTH,ABS,INT,FRAC,FACT,EXP,LN, *
* SQR (^ for power, SQRT for square root).                    *
***************************************************************
uses functions ar_anal_fonction, ar_eval_f of fonction.cpp,
               ar_aff_reel, ar_aff_reel_ln of armath.cpp.  
     here no use is made of optional type ar_nombre.         
-------------------------------------------------------------*/ 
#include "armath.h"

char   text[100];   //formula of function to analyze
int    n,ndata;     //ndata: number of points to evaluate
double dx,x,x1,x2;  //x increment,current x, x begin, x end
char   sx[20];      //auxiliary string
char   title[40];   //caption of function f(x)


void main()  {

  extern char *f_ana;  // Analyzed formula 

  printf("\n Analyze a real function F(x) defined by its equation\n");
  printf("\n Enter equation of Function f(x): "); scanf("%s", text);

  //see file Fonction.cpp
  ar_anal_fonction (text, (ar_fonction *) &ar_glob_f);
  //if compile of text is a success:
  printf("\n  Begin x: "); scanf("%lf", &x1);
  printf("\n  End x  : "); scanf("%lf", &x2);
  printf("\n  Number of points: "); scanf("%d", &ndata);
  printf("\n  Caption: "); scanf("%s", title);
  printf("\n\n");

  //Put ndata ordinates of F(x) in table Y
  printf(" %s\n\n", title);
  dx=(x2-x1)/(ndata-1);
  x=x1-dx;
  for (n=0; n<ndata; n++) {
    x += dx;
	//AR_OUI (yes) means: display rational approximation
	ar_aff_reel(" x=",x,AR_NON); ar_aff_reel_ln("  y=",ar_eval_f(x),AR_OUI);
  }
  printf("\n\n");

}

// end of file grfunct.cpp