Давид 5 задача

double Root(double E, double x0){
    double xp, xn = x0;
    do{
        xp = xn;
        xn = cos(xp);
    } while (fabs(xn-xp) >= E);
    return xn;
}

int main(){
    double eps = 1e-6, x0 = 1.0;
    double r = Root(eps, x0);
    cout<<r<<endl;
}