Bisection

//Author: Aryan Surana
//ID    : 2018B4A70937H

#include <bits/stdc++.h>
using namespace std;

float f(float x) {
    float result = 3*x - cos(x) - 1;
    return result;
}

int main() {
    float xl, xu, xm;
    cout << "Enter xl and xu: ";
    cin >> xl >> xu;
    char yn;

    do {
        cout << "Press y to start or n to exit: ";
        cin >> yn;
        float fxl = f(xl), fxu = f(xu), fxm = 0;
        xm = (xl + xu)/2;
        cout << "xm = " << xm;
        fxm = f(xm);
        cout << " f(xm) = " << fxm << "\n";
        if (fxm*fxl < 0) {
            xu = xm;
            continue;
        }
        else if (fxm*fxl > 0) {
            xl = xm;
        }

    }
    while (yn == 'y');
}