lab1 v4

#include <iostream>
#include <math.h>

using namespace std;

double f(double x);
double method_bisekcii(double start, double end, double epsil, double (*fun)(double));
double method_bisekcii(double start, double end, double epsil, int &n, double (*fun)(double));

int main()
{
    double a, b, result1, result2, epsil;
    int n = 0;
    cout << "Please, enter start, end: ";
    cin >> a >> b;
    cout << "Enter epsil: ";
    cin >> epsil;
    result1 = method_bisekcii(a, b, epsil, f);
    result2 = method_bisekcii(a, b, epsil, n, f);
    cout << "Koren1 = " << result1 << endl;
    cout << "Koren2 = " << result2 << " and n = " << n << endl;

    return 0;
}

double f(double x)
{
    return sin(x - 2) + 0.5;
}

double method_bisekcii(double start, double end, double epsil, double (*fun)(double))
{
    while (fabs(end-start)>epsil)
    {
        double center = (start+end)/2;
        if (f(start) * f(center) > 0)
            start = center;
        else if (f(center)==0)
            return center;
        else
            end = center;
    }
    return start;
}

double method_bisekcii(double start, double end, int count, double (*fun)(double))
{
    for (int i = 0; i < count; i++)
    {
        double center = (start+end)/2;
        if (f(start) * f(center) > 0)
            start = center;
        else if (f(center)==0)
            return center;
        else
            end = center;
    }
    return start;
}
double method_bisekcii(double start, double end, double epsil, int &n, double (*fun)(double))
{
    double result1, result2;
    n = 10;
    do {
        result1 = method_bisekcii(start, end, n, fun);
        result2 = method_bisekcii(start, end, 2*n, fun);
        n *= 2;
    } while (fabs(result1 - result2) > epsil*3);
    return result1;
}