//linda cobb
//winter 98-99
//bisection method for finding the roots of an equation

//**** caution
//algorithm fails if more than one root and brackets are 
//symmetric.. 

//added in hack to correct this error corrected algorithm 
//finds real roots if they exist.  even if there are two
//roots  bracketed area

//no longer fails on functions such as 2x^2 +3x +1 btwn +-9


#include <stdio.h>
#include <math.h>
//#include <time.h>

extern double bisection(double x1, double x2, double error);

double function(double x)
{

  printf("\n fn %lf", 3*x + 2*x*x);
  
  return (3*x + 2*x*x);
}



void main (void)
{
  //long t1,t2;
  
  double left, right, error;
  double solution;

  error = 0.0001;
  

  printf("\n Enter the left boundry =>  ");
  scanf("%lf", &left);
  
  printf("\n Enter the right boundry =>  ");
  scanf("%lf", &right);
  
  //printf("\n Enter the size of acceptable error =>  ");
  //scanf("%lf", &error);

  //t1 = clock();
  solution = bisection(left, right, error);
  //t2 = clock();

  printf( "\n the solution is %lf", solution);
  printf( "\n F of (solution) is %lf\n", function(solution));

  //  printf("Time = %7.2lf ms",
  //       1000.0*(double)(t2-t1)/(double)CLOCKS_PER_SEC);
}