Lecture 6 – September 14^th

Notes courtesy of Brent

Class Notes 09/14/06

-There are now 2 copies of the Ada 95 Language reference manual in CISAT Library available for 2 hour loans

- There is also an additional Ada Data Structures text on 2 hours reserve in the CISAT library.

-When using FIREFOX or Internet Explorer, you may not get the appropriate .exe extension upon downloading the compiler. If the download doesn’t have the extension .exe it won’t work properly

-Email Dr. Adams if you notice that the notes are not on the website.

-Get used to going to ADA 95 Reference Manual online.

-When you declare a new type of an array, REMEBER TO DECLARE A VARIABLE OF THAT TYPE!

-When you want to make a data file, for your program to read from make it a plain text file and then you can name it .in or .out

-When you submit files to Dr. Adams name your files using your name and the number it says in the assignment

- Yes, you can submit multiple files to the drop box. You can try zipping them together if you have multiple files. The first time you do this please also submit them separately so we can see if the zip works.

-https://users.cs.jmu.edu/adamses/web is our CS 240 website.

-If your’re having problems send Dr. Adams a note or put it on the discussion board found on Blackboard.

-The command to go the next line on a read statement is Ada.text_io.skip_Line() -- used in your exception handler when expecting an

-- integer and run into a character and the data is one element per line

-- if all of the data is on a single line, use Ada.text_io.get(ch); where

-- ch has been declared as a character to remove the problematic element from

-- the input buffer.

-If you know there are only going to be n numbers, declare an integer constant representing the desired number of items

-need a loop up to that constant

-Alternative way other than looping

-ada.integer_text_io.get(num1,num2,num3,num4,num5);

-For blackboard digital dropbox, you must ADD and then SEND!!!!

-You can not index just an integer, you have to declare a array type to be able to index

-Slides from today's lecture on chapter two can be reached via this link .

Representation of integers in the computer

- Sign magnitude

-One's Complement you have all positive numbers and +0 and a -0

-Two’s complement has only 1 representation for zero so it has one more number on the negative side than the positive side.

-Here is an example(I, Dr. Adams will fill this in later)

We discussed some of the slides for Chapter 2 – should study them over the weekend

-plus and minus sign are overloaded operators

-between two numbers means subtraction (infix -)

-before a single number means negative (prefix -)

- /= is a not equal (in other words it is equivalent to != in JAVA)

-you get attributes when talking about integers using the ticks and the tick(things) being attributes

-the advantage of ticks is you don't have to remember where your beginning or end is of that array - see example program

-Scalar data type has values which are ordered and each value is atomic

-Character

-Naturals

-Floats

-boolean is an enumerated data type which is ordered

-Discrete(Ordinal) data type in which each value (Except the first and last) must have a unique predecessor and successor

- example are: Integer, character, boolean

-Composite data type is a data type whose elements are composed of multiple data items(must have component parts)

-String (it is an array of characters)

-Date (has three component parts – month, day, year)

- array

- record

-Stack operations include POP, PUSH, PEEK, ISEMPTY, or ISFULL

-You NEED TO go back and look at the slides and understand them!

-GO look in the language reference manual for exceptions and figure out how to handle errors.

- Homework will be posted later.