Unit 8 - ArrayList

Unit 8 (ArrayList)
AP Computer Science 2020-21 / Dr. Kessner

Reading

• Eck Section 7.3 (ArrayList) http://math.hws.edu/javanotes/c7/s3.html

Code

Make sure to write full unit tests for these functions. Write at least one of these functions using a standard for loop, and at least one with a for-each loop.

Count lucky

A number is lucky if it is a multiple of 7 or ends in 7. Write a function that counts the number of lucky numbers in an ArrayList of integers.

countLucky({1, 2, 3}) -> 0
countLucky({7, 13, 17}) -> 2    
countLucky({107, 207}) -> 2    

Sum of squares

Write a function that takes a single ArrayList of doubles as input, and returns the sum of squares of the values.

sumOfSquares({0}) -> 0
sumOfSquares({1.0, 2.0, 3.0}) -> 14.0
sumOfSquares({2.0, 2.0, 2.0}) -> 12.0

Total Z name length

Write a function that takes an ArrayList of strings as input, and returns the total length of the strings that start with “z” or “Z”.

countZNames({"Dr. Kessner", "Dr. Sands"}) -> 0
countZNames({"Zorro", "zero", "zippy"}) -> 14