[t, y]=EULER_forward_ODE(f, t0, y0, tend, Niter)

欧拉向前逼近法求解微分方程初值问题

f定义了函数f（t，y）的

t0时的初始值定义吨

Y0的定义y的初始值-　[t, y]=EULER_forward_ODE(f, t0, y0, tend, Niter)

　Euler forward approximation method to solve IVP ODEs

　f defines the function f(t,y)

　t0 defines initial value of t

　y0 defines initial value of y