program sp300 implicit none real*8 w2 parameter( w2=3**2 ) integer i,Imax real*8 dt,Tmax parameter( dt=0.01, Tmax=20 ) ! sec real*8 t0,x0,v0 parameter( t0=0, x0=1, v0=0 ) real*8 t,x,xmid,v,vmid,a,amid t = t0 x = x0 v = v0 open(1,file='sp300.dat') write(1,'(a1,5x,a7,5x,a5,11x,a6)') '#','time(s)','x(m)','v(m/s)' write(1,'(1p3e15.7)') t,x,v Imax= Tmax/dt do i=1,Imax a = - * !PU vmid = v + * / xmid = x + * / amid = - * v = v + *dt x = x + *dt t = t + dt write(1,'(1p3e15.7)') t,x,v enddo close(1) stop end