// program chapter4_2.c - sinc() table using function 
//
// revised to put the function definition at the top
// and to use N points, suitable for plotting
//
#include <stdio.h>
#include <math.h>

#define PI (4*atan(1))
#define N 101

double sinc(double x)
{
   if (fabs(x) < 0.0001)
      return 1.0;
   else
      return sin(PI*x)/(PI*x);
}

int main(void)
{
   int k;
   double a=-4, b=4, x_incr, new_x;

   // printf("Enter endpoints a and b (a<b): \n");
   // scanf("%lf %lf",&a,&b);

   x_incr = (b - a)/(N-1);

   // printf("x and sinc(x) \n");

   for (k=0; k<N; k++)
   {
      new_x = a + k*x_incr;
      printf("%f %f \n",new_x,sinc(new_x));
   }

   return 0;
}