Unit 12 (2D Arrays) Assignment
AP Computer Science 2021-22 / Dr. Kessner

Reading

Code exercises

Make sure to write test code (not necessarily full unit tests) to print the contents of your arrays and demonstrate/verify they have the values you think they have.

Array initialization

a) Declare and initialize a 10x10 array of integers with 1 on the diagonal (i.e. where i == j) and 0 everywhere else.

b) Declare and initialize a 2D array of Strings (any size).

c) Declare and initialize a 5x5 array of doubles with the following values. You must use a loop.

    11.0  12.0  13.0  14.0  15.0
    21.0  22.0  23.0  24.0  25.0
    31.0  32.0  33.0  34.0  35.0
    41.0  42.0  43.0  44.0  45.0
    51.0  52.0  53.0  54.0  55.0

d) Declare and initialize a 6x5 array of integers with the following values. You must use a loop.

    1 1 1 1 1
    2 2 2 2 2 
    3 3 3 3 3 
    4 4 4 4 4 
    5 5 5 5 5 
    6 6 6 6 6

Computations on 2D arrays

a) Write a function that takes a 2D array of integers as input and returns the smallest.

b) Write a function that calculates the sum of a 2D array of floats.

c) Write a function that takes a 2D array of Strings as input, and counts the number of strings that start with the letter “A”.

2D arrays of objects

a) Write a class Rectangle. Include the following:

  • private member variables for the name (String), width and height (doubles)
  • a constructor that sets these member variables
  • public accessor functions for the member variables
  • public functions to calculate the perimeter and area

b) Write a function that takes a 2D array of Rectangle objects as input and returns the average perimeter.

c) Write a function that takes a 2D array of Rectangle objects as input and returns the object with the greatest area.