Programming I (CSC 216)

• Examine the code Oct1 and Oct2 (below).
  1. What do they do? Why are they considered zig-zag patterns?
  2. Which one is the most efficient in term of number of instructions? Explain.
  3. Which program contains more semantic information? Explain.
  4. In Oct2, modify path and pathBack to create the pattern in the figure below. Explain the relationship between path and pathBack.
  5. Modify path and pathBack to create your own interesting pattern.

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  File content not available for Oct2.java
  
  

• Examine the code Oct3.

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  1. Which program has the fewer lines of code Oct3 or Oct2?
  2. For the same area of the pattern which uses more paints?
  3. How does Oct3 differ from the standard expand program?
  4. How difficult is it to create your interesting pattern using Oct3's algorithm?
  5. Write a program based on Oct3 that uses triangles instead of octagons for the basis of the pattern.

• Low-level computations on a computer are achieved by using binary: ones and zeros. In PolygonR&D, similar computations can be achieved by using coloured squares. This means that we will interpret squares colours as having a numeric value. We will examine ways of representing numbers as uniary (tallies --like base 1) and as binary (base 2).
• Examine the code UniAdd.

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  1. Insert comments into the UniAdd codes so that the meaning / purpose of the code is clearer.
  2. How many ifs in total are used to add 111 with 111?
  3. Sometimes the random numbers are too big or too small to be interesting. Convert the code so that the numbers to be added are more than 2 and less than 8.
  4. Translate the code so that the sum displays in binary.
  5. Rewrite rNum so that it creates random binary numbers between 4 and 32.
  6. Rewrite AddNum and it's subprograms so that it correctly adds binary numbers.
  7. Rewrite AddNum so it adds column-wise.
  8. Compare the ifs used during the addition of 111 with 111 for each of the binary AddNums (non-columns and column-wise).
  9. What are the biggest number that can be added (without changing the program with scaling etc) in the original UniAdd and the binary version of the code? What if ternary (base 3) was used instead?
• Hints.... look at the old assignment 3.

Assignment 2: describing algorithms

• This assignment examines algorithms that rely on conditional behavior. Previous algorithms that dealt with elaborating an existing loop by inserting spacers or interleaving a zig-zag of odd-sided polygons implicitly contained a condition--stop if you have completed the loop. In these new algorithms the conditions serve a more important role; they determine how the pattern develops.
• Part A
  • Consider these two different ways for creating this pattern in Tileland:
    1. have the building block be "hexagon orange square blue turn"
    2. have the building block be "square blue turn hexagon orange"
  • Use each of the building blocks to create the pattern.
  • Questions
    • Identify the grid and the spacers for each pattern.
    • Describe in words the algorithms that you need to use for each building block.
    • Describe with pictures in a diagram the algorithms that you need to use for each building block.
    • Which of the methods of is more efficient for this pattern?
  • The focus on the spacers or the grid tiles is different. Since neither the spacers nor the grid is complex, the pattern is not difficult to construct.
  • For these patterns, use only one (the most efficient one) of the algorithms to construct these patterns.
  • More Questions
    • Describe with pictures in a diagram the algorithms that you used to make these patterns.
    • For each pattern, what is the better focus for the constructions. Why?
• Part B
  • Create this pattern and pay particular attention to how you construct it. It may require you to make it many times and perhaps a few different ways: in particular make sure that you use one that relies on cutting and pasting.
  • Questions
    • Describe how the algorithm you used to construct this pattern. What made this pattern more difficult than the above patterns?
    • Explicitly write down a sequence of character that will construct this pattern. For example, a sequence of letters that creates a square grid is :
      

      4 r t a x 
      v v v v v t
      v v v v t
      v v v v t
      v v v t
      v v v v t
      v v v t
      v v v v t
      v v v t
      v v v t
      v v v v t
      v v v t
      v v v t
      v v v v t
      v v v t
      v v v t
      v v v t
      v v v v t
      v v v t
      v v v t
      v v v t
      v v v v t
      v v v t
      v v v t
      v v v t
      v v v t
      v v v v t
      v v v t
      v v v t
      v v v t
      v v v t
      v v v v t
      ...
      Be wary--this is a difficult task.
      

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  Assignment 1: making polygon loops and stars

  • This assignment examines algorithms and their effectiveness. An algorithm has a number attributes that are interesting: correctness, efficiency, and simplicity.
  • Part A
    • Consider at least two different ways for creating this pattern in Tileland.
    • Questions
      1. Describe two ways that you created the pattern using words, then try to describe it using diagrams with arrows.
      2. Compare the twos way that you made the pattern in terms of correctness, efficiency, and simplicity.
      3. Write up a definition for algorithm (state your resource).
  • Part B
    • 
    • Questions
      1. What are the minimum number of instructions to create these patterns in TileLand? Describe the method you used to construct these pattern.
      2. What is the minimum number of mouse clicks?
      3. Create your own interesting repetitive pattern that does not require a lot of clicks but has a lot of instructions. What makes the pattern interesting?