The object manager would contain a vector of objects. Every game object you have should inheirit from this object class. Each object should have an update() and a draw() method. Update should move the object on the screen based on velocity, framerate, user input, etc. It should also animate the object. The draw() method should just draw the object to the screen based on vars the update() method has updated. Then your object manager should just run through each object in the vector and call update(). After that is done, run thorugh each object and call draw().
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