Here are three classes that meet the requirements outlined in the homework: 1. Employee class with get/set methods for name, salary, and method to calculate yearly salary with a raise. 2. Invoice class with get/set methods for part number, description, quantity, price, and method to calculate invoice amount. 3. Date class with get/set methods for month, day, year, and method to display date in MM/DD/YYYY format.

1. Lesson 2’s Homework
1. Define a function max() that takes two numbers
as arguments and returns the largest of them.
Use the if-then-else construct available in
Javascript.
2. Define a function that takes three numbers as
arguments and returns the largest of them
1

2. 3. Define a function that computes the reversal of
a string. For example, "jag testar" should print
the string "ratset gaj”.
4. Write a function that takes an array of words
and returns the length of the longest one.
5. Write a function that returns the area of a
triangle when 3 sides are given
Lesson 2’s Homework
2

3. 6. Write a function that returns all prime numbers that
smaller than 100
7. Write a function that takes a character (i.e. a string of
length 1) and returns true if it is a vowel, false
otherwise.
8. Define a function sum() and a function multiply() that
sums and multiplies (respectively) all the numbers in
an array of numbers. For example, sum([1,2,3,4])
should return 10, and multiply([1,2,3,4]) should return
24.
Lesson 2’s Homework
3

4. 9. Write a function charFreq() that takes a string
and builds a frequency listing of the characters
contained in it. Represent the frequency listing
as a Javascript object. Try it with something like
charFreq("abbabcbdbabdbdbabababcbcbab")
10. Write a function int fib(int n) that returns Fn. For
example, if n = 0, then fib() should return 0. If n
= 1, then it should return 1. For n > 1, it should
return Fn-1 + Fn-2
Lesson 2’s Homework
4

5. New Exercises
1. Write a function that takes a number and returns all even
number from 0 to that number
2. Write a function that takes a number and returns its
factorial
3. Given an integer size, return array of size zeros
4. Write a function that determines if a number is in a given
range.
5. You are given a two-digit integer n. Return the sum of its
digits.

6. New Exercises
6. A password is complex enough, if it meets all of the following conditions:
• its length is at least 5 characters;
• it contains at least one capital letter;
• it contains at least one small letter;
• it contains at least one digit.
Write a function that takes a password string and return where that string is complex
enough
7. A perfect array is an array in which each element is equal to the length of this array.
Check if a given array is perfect.
1. for [2, 2] output should be true
6. for [4, 4, 4] or [2, 1] output should be false

7. New Exercises
8. Given the sequence of integers, check if it is strictly increasing.
1. for [1, 3, 8] output should be true
2. for [2, 2, 3] output should be false
8. Each day a plant is growing by upSpeed meters. Each night
that plant's height decreases by downSpeed meters due to the
lack of sun heat. Initially, plant is 0 meters tall. We plant the
seed at the beginning of a day. We want to know when the
height of the plant will reach a certain level. Write a function that
takes upSpeed, downSpeed, maxHeight and returns the
amount of days are needed to reach maxHeight

8. 10. Given integers L and R, find the number of different
pairs of integers A and B such that L <= A <= R and L
<= B <= R and A3 = B2. Note that A and B may even
coincide (A = B = 1 is one of the possibilities).
1. for L=1, R=4 output should be 1 - (1,1)
2. for L=1, R=8 output should be 2 - (1,1) and (4,8)
10. Change the capitalization of all letters in a given
string.

9. Lesson 3
OOP in JS

10. History of programming language
Early programming languages such as Basic, Fortran... are
unstructured and allow spaghetti code. Programmers used
“goto”and “gosub” to jump to anywhere in the programs.
• Hard to understand
• Error-prone
• Difficult to modify
10

11. Next came the new
structural programming
paradigm with languages
like Algol, Pascal,C...
History of programming language
• Use of looping structures: for, while, repeat, do-while
• Programs as a series of functions/procedures
• Program source code focus on representing
algorithms
11

12. Limitation of procedural programming
• Data are separated from processes
• Passive data, active processes
• No guarantee of data consistency
and constraints
• Difficulty in code maintenance
• Processes are scattered, but data
are public
• Each function must understand the
data structures
12

13. Object-oriented programming
• Data come together with related processing code
• Allow for guarantee of data consistency and constraint
• Easier maintenance
13

14. Data & Processes
Relationship
14

15. What’s OOP
• OOP
• Map your problem in the real world
• Define “things” (objects) which can either do something or have something
done to them
• Create a “type” (class) for these objects so that you don’t have to redo all
the work in defining an objects properties and behavior
• An OO program: “a bunch of objects telling each other what to do by sending
messages”. (Smalltalk)
15

16. Important OO concept
• Abstraction
• Objects & Class
• Object state and behavior
• Object identity
• Encapsulation
• Information/implementation hiding
• Inheritance
• Polymorphism
16

17. Abstraction
• Abstraction means working with something we
know how to use without knowing how it works
internally
• Ex: TV
• Don’t need to know the inner workings
• Use: A remote control with a small set of
buttons -> Watch TV
17

18. Objects
• Attributes
• Variables holding state information of the
object
• Methods
• Operations/services performed on the
object.
• State
• Given by object’s internal data (attributes)
• Behavior
• Produced by object’s methods
18

19. Objects
• Identity
• Objects in any of its states are unique entities (with
unique addresses in memory)
• Different objects could have same values for data
(same state)
• An object is manipulated via its handle
• In C++: pointers and references
• In Javascript: object references

20. Encapsulation/Information hiding
• Encapsulation:to group related things together, so as to use one name to
refer to the whole group.
• Functions/procedures encapsulate instructions
• Objects encapsulate data and related procedures
• Information hiding: encapsulate to hide internal implementation details
from outsiders
• Outsiders see only interfaces
• Programmers have the freedom in implementing the details of a
system.
• The only constraint on the programmer is to maintain the interface

21. Inheritance
Animal
name
•eat()
•breathe()
Duck
name
•swim()
•fly()
Dog
name
•bark()
•run()
Coral
name

22. Inheritance
• The general classes can be specialized to more
specific classes
• Reuse of interfaces & implementation
• Mechanism to allow derived classes to possess
attributes and operations of base class, as if they
were defined at the derived class
• We can design generic services before
specializing them

23. Polymorphism
• Objects of different derived
classes can be treated as if
they are of the same class –
their common base class
• Objects of different classes
understand the same
message in different ways
• http://jsbin.com/repoqapoto/
edit?js,console

24. Home Work
1. Create a class called Employee that includes three
pieces of information as instance variables a first
name, a last name and a monthly salary. Provide a
set and a get method for each instance variable. If
the monthly salary is not positive, set it to 0.0. Write
a test that demonstrates class Employee's
capabilities. Create two Employee objects and
display each object's yearly salary. Then give each
Employee a 10% raise and display each
Employee's yearly salary again.

25. Home Work
2. Create a class called Invoice that a hardware store
might use to represent an invoice for an item sold at the
store. An Invoice should include four pieces of
information as instance variables a part number, a part
description, a quantity of the item being purchased and
a price per item. Provide a set and a get method for
each instance variable. In addition, provide a method
named getInvoiceAmount that calculates the invoice
amount (i.e., multiplies the quantity by the price per
item), then returns the amount. If the quantity is not
positive, it should be set to 0. If the price per item is not
positive, it should be set to 0.0.

26. Home Work
3. Create a class called Date that includes three
pieces of information as instance variables a
month , a day and a year. Provide a set and a
get method for each instance variable. Provide
a method displayDate that displays the month,
day and year separated by forward slashes (/).