# COMP-200: Intro to Computer Systems
## Assignment 1
### mo khan - 3431709

Choose ONE exercise each from Chapters 2 and 3

Chapter 2:

4. Write an algorithm that gets the price for item A plus the quantity
   purchased. The algorithm prints the total cost, including 6% sales tax.

    Pseudocode

    ```plaintext
    Get values for `price` and `quantity`
    Set the value of `tax` to 1.06
    Set the value of `total` to `price` multiplied by `quantity` multiplied by `tax`
    Print the value of `total`
    ```

    Ruby code

    ```ruby
    def calculate_total(price, quantity, tax = 0.06)
      (price * quantity) * (1.0 + tax)
    end
    ```

Chapter 3:

21. Use the binary search algorithm to decide whether 35 is in the following
    list: `3, 6, 7, 9, 12, 14, 18, 21, 22, 31, 43`

    Pseudocode

    ```plaintext
    Get the list of numbers and assign to variable `items`
    Get the target number and assign to variable `target`
    Set variable `min` to 0
    Set variable `max` to total # of `items`
    Set variable `mid` to `max - min / 2`
    Set variable `found` to No
    while (mid > min && mid < max)
      Set the variable `current` to `items` at index `mid`
      if current = target
        Set variable `found` to Yes
        Set variable `mid` to `min - 1`
      else if target > current
        Set variable `min` to the value of `mid`
        Set the variable `mid` to `((max-min) / 2) + min`
      else
        Set variable `max` to the value of `mid`
        Set the variable `mid` to `((max-min) / 2) + min`
      end
    end of loop
    If Found = Yes
      print Found
    else
      print Not Found
    stop
    ```

    Ruby code

    ```ruby
    def bsearch(target, items)
      min = 0
      max = items.size
      mid = (max - min) / 2

      while (mid > min && mid < max) do
        current = items[mid]

        if target == current
          return true
        elsif target > current
          min = mid
        else
          max = mid
        end

        mid = ((max - min) / 2) + min
      end

      return false
    end
    ```

    What numbers will be compared with 35?

    1. 14

      | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 |
      | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
      | 03 | 06 | 07 | 09 | 12 | 14 | 18 | 21 | 22 | 31 | 43 |

    2. 22

      | 00 | 01 | 02 | 03 | 04 |
      | -- | -- | -- | -- | -- |
      | 18 | 21 | 22 | 31 | 43 |

    3. 31

      | 00 | 01 |
      | -- | -- |
      | 31 | 43 |

    4. 43

      | 00 |
      | -- |
      | 43 |