#include<stdio.h>
#include<stdlib.h>
#include"vector.h"
template<class A> void eiler(A & y, double tau, int nstep, A(*f)(A, double));

template<class A> void eiler(A & y, double tau, int nstep, A(*f)(A, double)) {
    for (int i = 0; i < nstep; i++)y = y + tau * f(y, i * tau);
}
Vector right(Vector y, double t);

Vector right(Vector y, double t) {
    Vector tmp(2);
    tmp(1) = y(2);
    tmp(2) = y(1);
    return tmp;
}

void main() {
    Vector y(2);
    double tau = 0.001;
    int nstep = 10;
    y(1) = 0.1;
    y(2) = 0.01;
    eiler(y, tau, nstep, right);
    y.print();
}