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Inheritance
and
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is-a
relationship
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“Is-a'' also
implies, that we can use a circle everywhere
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where a point is
expected. For example, write a function or
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method, say
move(), which should move a point in x
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direction can be written
as follows.
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move(Point
apoint, int deltax) {
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apoint.setX(apoint.getX() + deltax)
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}
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As a circle
inherits from a point, you can use this function
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with a circle
argument to move its center point and, hence,
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the whole circle:
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