/* integroi.c */
#include <stdlib.h>
#include <stdio.h>
#include <math.h>

double integroi(double x1, double x2, int tiheys)
{
  double x,dx,summa=0;

  dx = (x2-x1)/tiheys;

  for (x=x1+dx/2 ; x<x2; x+=dx)
    summa += sin(x)*dx;

  return summa;
}

int main(void)
{
  printf("Integraali sin(x) v„lilt„ [0,pi] on noin %7.5lf\n",
          integroi(0,M_PI,100));
  return 0;
}