Course overview
How geeks see the (object oriented) world
Skills : changing property values
Concepts : object, class, property (attribute), value, data type
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Where does this topic fit?
• Internet concepts
– Applications
– Technology
– Implications
• Internet skills
– Application development
– Content creation
– User skills
To a geek, the world is made up of objects that have properties and those properties have values .
That is kind of abstract – how about an example?
Let’s try a second example …
Regular person: That is a pretty girl!
Geek: That is an instance of the class person.
• The value of its height property is 64 inches.
• The value of its weight property is 130 pounds.
• The value of its age property is 25.
• The value of its hair-color property is black.
Regular person: Cool old car!
Geek: That is an instance of the class car.
• The value of its body-color property is ___.
• The value of its wheel-color property is ___.
• The value of its number-of-wheels property is ___.
• The value of its number-of-doors property is ___.
• The value of its manufacturer property is ___.
• The value of its model property is ___.
• The value of its year-manufactured property is ___.
• The value of its horsepower property is ___.
Instances of the class person
What are some of the properties of persons?
What values can they take on?
These objects might be on a computer screen
What class of object are these?
Instances of the class line
What are some of the properties of a line?
Different values of the color property of a line
Y
Location of a line on the screen
x
Data type validity
My computer cost 500 dollars.
My computer cost purple dollars. ( fail )
I am six feet tall.
I am purple feet tall. ( fail )
Payday is Friday.
Payday is 500. ( fail )
My phone number is 310-123-4567.
My phone number is 310-four567. ( fail )
Right click to see properties and their values
The Alto at Xerox PARC, 1973
Set property values with a dialog box
Summary
Self-study questions
What are five properties of instances of the class dog?
For each of the properties you listed, state a possible value.
What are five properties of instances of the class house?
For each of the properties you listed, state a possible value.
Find three examples of objects with properties in Microsoft
PowerPoint
We saw that right clicking on an object often brings up a property dialog box. What class of object is the following dialog box for?
Resources
Objects in the JavaScript programming language: http://www.w3schools.com/js/js_obj_intro.asp
