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[Verano 2016 - Ive - Coralys]
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-One commonly used programming technique is *recursion*. With this technique, problems are solved by solving similar problems, but for smaller cases. We can construct sets of objects or tasks using *recursive rules* and *initial values*. *Recursive functions* are functions that are self-invoking, using smaller sets or elements each time, until reaching a point where the initial value is used instead of self-invoking. Fractals are an example of figures that can be created using recursion. In this laboratory experience, you will practice the definition and implementation of recursive functions to draw self-similar objects (fractals).
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+One commonly used programming technique is *recursion*. With this technique, problems are solved by solving similar problems, but for smaller cases. We can build sets of objects or tasks using *recursive rules* and *initial values*. *Recursive functions* are functions that are self-invoking, using smaller sets or elements each time, until reaching a point where the initial value is used instead of self-invoking. Fractals are an example of figures that can be created using recursion. In this laboratory experience, you will practice the definition and implementation of recursive functions to draw self-similar objects (fractals).
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The exercises in this laboratory experience are an adaptation of https://sites.google.com/a/wellesley.edu/wellesley-cs118-spring13/lectures-labs/lab-6-turtle-recursion.
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Can you see the recursive behavior in this figure? Notice that `branch(0,90)` is only a vertical segment (a segment in an angle of 90 degrees); `branch(1,90)` is `branch(0,90)` with two segments inclined in its top. More precisely, `branch(1,90)` is `branch(0,90)` with a `branch(0,60)` and a `branch(0,120)` in its top. Similarly, `branch(2,90)` is `branch(0,90)` with two `branch(1,90)` inclined in the top. That is, `branch(2,90)` is:
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`branch(0,90)` with a `branch(1,60)` and a `branch(1,120)` in its top. Notice that $$60=90-30$$ and $$120=90+30$$.
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This way we can express `branch(n,A)` as a composition of branches with $$n$$ smaller and inclined branches. Code 1 provides a way of expressing `branch` as a recursive function.
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## Deliverables
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-1. Use "Deliverables" in Moodle to upload the `boxes.cpp` and `main.cpp` files. Remember to use good programming techniques, include the names of the programmers involved, and to document your program.
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+1. Use "Deliverables" in Moodle to upload the `boxes.cpp` and `main.cpp` files. Remember to use good programming techniques, include the names of the programmers involved, and document your program.
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---
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[4] http://www.coolmath.com/fractals/images/fractal5.gif
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-[5] "Fractal tree (Plate b - 2)". Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Fractal_tree_(Plate_b_-_2).jpg#mediaviewer/File:Fractal_tree_(Plate_b_-_2).jpg
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+[5] "Fractal tree (Plate b - 2)". Licensed under Public domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Fractal_tree_(Plate_b_-_2).jpg#mediaviewer/File:Fractal_tree_(Plate_b_-_2).jpg
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