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CS1 Course Site
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Wait , WAIT !!What's that word ? ( Class Notes ( without definitions ) )
Monday September 18 , 2000
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For lab this week
- go
- If the ``Colatz lab'' is not finished, finish it.
- If the ``web site' Developement Lab'' is not finished, finish it.
- If the ``Programming assignment'' (GPS) is not finished, finish it.
- Work on your web site, + Shape your good work + your enthusiasm for the opportunity to develope a cool site with your instructor.
Some comments on the ``class notes'' section of the site...
- You are welcome to (and encouraged to) try to render the lectures in a fairly faithful manner.
- Alternatively, you might simply write a paragraph or two summarizing the lecture for each class
\\ section {Class Notes}
\\ subsection {Monday, ------}
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\\ vs
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Remark
blue.shapes. * is off limits for the current programming assignment.
Specification of the Rectangle Class
Constructor
new Rectangle (< double >, < double >) --- > < rectangle >
Operators
< rectangle > .length () ----- > < double >
< rectangle > .width () ------ > < double >
< rectangle > .area () ------- > < double >
< rectangle > .perimeter () -- > < double >
< rectangle > .diagonal () --- > < double >
Commands
< rectangle > .display ()
Suppose we have a city block of length 480 and width 300 partitioned into 16 rectangular lots...
Tasks
- Model the block and a lot in terms of rectangles.
double blockLength = 480;
double blockWidth = 300;
Rectangle block = new Rectangle (blockLength, blockWidth);
double lotLength = blockLength / 8;
double lotWidth = blockWidth / 2;
Rectangle lot = new Rectangle (lotLength, lotWidth);
- Display the distance from one corner of the block to the far corner.
IO.println (block.diagonal ());
- Declare a variable called pc and bind it to the percent of the block, taken up by one lot.
double pc = (lot.area () /block.area ()) * 100;
Problem
What is the surface area of a cylinder of height 28.5 and D of 11.6?
Note
The surface area of the cylinder equals:
- the area of the top +
- the area of the bottom +
- the area of the side
Note
We are using problem decomposition
Note
We can explode the cylinder into circles and rectangles.
The Java program
< CLASS > ----- > SurfaceAreaApp
< NEEDS > ----- > import blue.shapes. *;
< PROGRAM > --- >
/ /Establish the given information
double cylinerHeight = 28.5;
double cylinderDiameter = 11.6;
/ /Create the top
double topRadius = cylinderDiameter / 2;
Circle top = new Circle (topRadius);
/ /Create the bottom
double bottomRadius = cylinderDiameter / 2;
Circle bottom = new Circle (bottomRadius);
/ /Create the side
double sideHeight = cylinderHeight;
double sideLength = top.perimeter ();
Rectangle side = new Rectangle (cylinderHeight, cylinderLength);
/ /Compute the surface area of the cylinder
double sa = top.area () + bottom.area () + side.area ();
/ /Display the result
IO.println ( ``The surface area = ``+ sa + ``Square units.'');
A note on string Manipulation
< string > + < string > --- > < string >
Ex
``Sun'' + ``shine'' = ``sunshine''
< string > + < double > = < string >
Ex
``x = ``+ 5.2;
means ``x = ``+ ``5.2''
means ``x = 5.2''
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