#include <stdio.h>
#include <math.h>
/* newtnop.c : 1999 3 9 by Oguni */
#define N 20
double func(double x);
double deriv2(double x);
double deriv1(double x);
main(){
  int itr[2]={20,1}, it;
  double tol=0.000001, x[N];
  x[0]=-0.5;
  newtnop(x,tol,itr); it=itr[1];
  printf("%d %f\n", it, x[it]);
}
/* function */
double deriv2(double x)
{
  double y;
  y=-sin(x)+cos(x); return y;
}
double deriv1(double x)
{
  double y;
  y=cos(x)+sin(x); return y;
}
double func(double x)
{
  double y;
  y=sin(x)-cos(x); return y;
}
newtnop(x,tol,itr)
double x[N],tol;
int itr[2];
{
  int it;
  double res=100000.0, xnew, p;
  it=0;
  while (itr[1]<itr[0]){
    p=-deriv1(x[it])/deriv2(x[it]); x[it+1]=x[it]+p; res=fabs(p);
    it++;
    printf("%d %f %f\n", it,x[it],p);
    if (res<tol) { tol=res; itr[1]=it; return; }
  }
  itr[1]=it; return;
}