模拟蚂蚁和食蚁兽的生存规律。在20X20的网格世界里，每个生物每次可向四个方向移动（但不会移除网格边缘），食蚁兽会吃掉在他目标处的蚂蚁-The goal for this programming project is to create a simple 2D predator-prey simulation.

In this simulation the prey are ants and the predators are doodlebugs.

These critters live in a world composed of a 20x20 grid of cells.

Only one critter may occupy a cell at a time. The grid is enclosed, so a critter is not allowed to move off the edges of the world.

Time is simulated in time steps.

Each critter performs some action every time step.