// generate random data

#include <stdio.h>

#include <math.h>

#include <strings.h>

#include <stdlib.h>

//# define M_PI 3.14159265358979323846  /* pi */

 

#define XMIN  0.2

#define XMAX  1.2

#define YA   -1.5

#define YB    0.8

#define YC   -0.7

#define YR    0.2

 

/* Uniform random number from [0,1] */

double random_num()

{

  return (double)rand() / (double)RAND_MAX;

}

 

int main( int argc, char *argv[] )

{

  int    N, i;

  double x, y;

 

  N = atoi(argv[1]);

  printf("# %d\n", N);

 

  for (i=0; i < N ; i++)

    {

      x = XMIN + (XMAX-XMIN)*random_num();

      y = YA + YB*x + YC*x*x + YR*random_num();

      printf("%f\t%f\n", x, y);

    }

 

  return EXIT_SUCCESS;

}