Definite_Integration.c
From: Craig Schroeder [schroeder@santel.net]
Sent: Thursday, December 23, 1999 01:59
To: JoshS@santsys.com
Subject: Definite Integration.

/* This program performs definite integration.  It integrates
a given function, f(x), on the interval [a,b].  N can be set as
a variable to control precision.  The algorithm in use is Simpson's
Rule, and it is VERY fast. */

#include 
#include 

double f(double x) {return cos(x)+sin(x);}  // function to integrate.

double I(double (*f)(double), double a, double b, unsigned long N)
{
  double w=(b-a)/N, s=0, k=a;
  for(unsigned long i=0; i