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27 lines
959 B
27 lines
959 B
2 years ago
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Exercise 2.2: Consider the problem of
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representing line segments in a plane. Each segment is represented as a pair
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of points: a starting point and an ending point. Define a constructor
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make-segment and selectors start-segment and end-segment
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that define the representation of segments in terms of points. Furthermore, a
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point can be represented as a pair of numbers: the
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x
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coordinate and the
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y
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coordinate. Accordingly, specify a constructor make-point and
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selectors x-point and y-point that define this representation.
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Finally, using your selectors and constructors, define a procedure
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midpoint-segment that takes a line segment as argument and returns its
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midpoint (the point whose coordinates are the average of the coordinates of the
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endpoints). To try your procedures, you’ll need a way to print points:
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(define (print-point p)
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(newline)
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(display "(")
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(display (x-point p))
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(display ",")
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(display (y-point p))
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(display ")"))
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