#include <iostream>
    using namespace std;

double m = 1;
double k = 1;

double euler(double, double, double, double, double);


int main()
{
    cout << "Euler:  " << euler(1, 0, 0, .000001, 10) << endl;
}

double euler(double x, double v, double t, double delta, double target)
{
    if(t >= target)
        return x;
    
    double a = -(k / m) * x;
    x+= (v * delta);
    v+= a;
    t+= delta;
    
    //cout << "x:  " << x << "\tv:  " << v << " \tt:  " <<t << "\tdelta:  " << delta << "\ttarget:  " <<target << endl;

    return euler(x, v, t, delta, target);
}