program fly_plot

      write(*,*)'Please give me inital x'
      read(*,*)xini
      write(*,*)'and initial y'
      read(*,*)yini
      write(*,*)'initial Vx?'
      read(*,*)vx
      write(*,*)'initial Vy?'
      read(*,*)vy

      i_dummy=pgopen('/xwin')
      call pgenv(0.0,10.0,0.0,10.0,1,0)
      dt=0.000001

      x=xini
      y=yini
      
      do while(y>0)
        ax=0
        ay=-9.8
        vx=vx+ax*dt
        vy=vy+ay*dt
        x=x+vx*dt
        y=y+vy*dt
        call pgpt(1,x,y,-1)
      end do
      write(*,*)'Distance=',x,'Hight=',y
      call pgclos
      end