#include <stdio.h>

/* Upper camel case */
double f (double x);
int SameSign(double x, double y);
double MiddleOf(double x, double y);
int IsSmallNumber(double x);

double FindRootBetween(double a, double b)
{
    double l = a, u = b;
    while (!IsSmallNumber(f(middleOf(l, u)))) { 
        if(SameSign(f(middleOf(l, u)), f(u)))
            u = middleOf(l, u);
        else 
            l = MiddleOf(l, u);
    }
    return MiddleOf(l, u);
}  

int main (void)
{
    FindRootBetween(-3.0, 5.0);
}