Plot function for two moving points with different velocities

I have the following code but it gives an error undefined function or variable 'x'. Can anyone please help me in this? plot(x, y, 'b');

car = line([], [], 'MarkerSize', 10, 'Color', 'r');

carx = x(1); cary = y(1);

numxy = length(x);

aimidx = 2;

numv = length(v);

vidx = 0;

speed = 0;

while true

    if speed <= 0

      carm = 'x';

      set(car, 'XData', carx, 'YData', cary, 'Marker', carm);

      drawnow;

      if vidx >= numv || aimidx > numxy

        break;  %done following path

      end

      vidx = vidx + 1;

      speed = v(vidx);

      continue;

    end

    deltax = x(aimidx) - carx;

    deltay = y(aimidx) - cary;

    aimdist = sqrt(deltax.^2 + deltay.^2);

    if aimdist <= speed

      carx = x(aimidx);

      cary = y(aimidx);

      aimidx = aimidx + 1;

      speed = 0;  %flag to draw current point and move to next v

      continue;

    end

    carx = carx + speed * deltax ./ aimdist;

    cary = cary + speed * deltay ./ aimdist;

    if abs(deltax) >= abs(deltay)

      if deltax > 0

        carm = '>';

      else

        carm = '<';

      end

    elseif deltay > 0

      carm = '^';

    else

      carm = 'v';

    end

    set(car, 'XData', carx, 'YData', cary, 'Marker', carm);

    drawnow;

end

Answer 1

[Image Analyst]

If the first line of your code is this:

plot(x, y, 'b');

then why do you think x and y should have any values when you call plot()? You need to set them equal to something before you call plot.