Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
59 Cards in this Set
- Front
- Back
|
Elementary data item
|
A single item such as a number or character. What we concentrate on in this course.
|
|
|
Aggregate data item
|
A group of numbers or characters. Sometimes called a data structure. Deals with arrays. Character strings. etc.
|
|
|
Program Data Elements vs Data Types
|
Programs have different types of elements that hold data created by the programmer to reference data. These elements we speak of can hold different types of data.
|
|
|
Variable element
|
A data item with a name and that contains a value that may change as the program executes
|
|
|
Constant element
|
A data item with a name and that contains a value that remains the same during the execution of the program no matter what. Usually in capital letters.
|
|
|
Literal element
|
A constant whose name is the representation of it's value. Ex: "A" or "100". It's literal, see?
|
|
|
Integer data type
|
Whole numbers, positive, negative or zero
|
|
|
Floating Point data type
|
Numbers that may have post-decimal digits
|
|
|
Character data type
|
Keyboard characters plus some special chars
|
|
|
Boolean data type
|
Only two values available: true or false
|
|
|
String data type
|
A group of characters. The only aggregate data type we cover.
|
|
|
Identifier
|
Variable, constant, or function, etc. Meaningful names describing the kind of data stored.
|
|
|
Value vs Representation
|
These are two different things. There's a CONCEPT of numeric value in a represented number and then there is HOW that value is represented.
|
|
|
Decimal Number System
|
Base 10. Grouped by powers of ten. Digits 0-9. Commonly used in society.
|
|
|
Binary Number System
|
Base 2. Grouped by powers of 2. Consists of bits: 0 and 1. It is used as a computer storage system and known for reliability.
|
|
|
Hexadecimal Number System
|
Base 16. Grouped by powers of 16. Consists of hex digits... 0, 1-9, A-F. Known to conserve space... makes for easy conversion to and from binary.
|
|
|
Data Representation
|
Refers to the manner in which data is stored in the computer. Several different formats for data storage.
|
|
|
Data overflow, uh oh!
|
Since we have finite storage, it is possible to overflow a storage location by trying to store too large a number etc. It is up to the programmer to choose the data type with a length that wont overflow. Knowing how numbers are represented in storage helps one to understand this.
|
|
|
Data forms
|
Characters, numbers, graphical, media, etc
|
|
|
Bits
|
Binary digits... What all data is stored in the computer as
|
|
|
Bit Pattern
|
A universal storage format for all data types
|
|
|
More on Bits
|
Smallest unit of data stored in a computer. Value of 0 or 1. Is like a switch: on (1) or off (0). Bits are stored electronically in RAM and auxiliary storage devices by two-state digital circuits. It is the software that stores and interprets the pattern.
|
|
|
Process of data retrieval
|
Data is coded then stored and when retrieved it is decoded
|
|
|
Byte
|
A byte is a string of 8 bits. Called a Character when the data is text.
|
|
|
Character
|
A string of 8 bits that is text
|
|
|
Binary Number
|
A number represented by 0s and 1s. Ex: 10010101
|
|
|
ASCII
|
American Standard Code for Information Interchange. The scheme used to assign a bit pattern to each of the characters available. Charts come in different flavors: 7bit strings, some 8, some binary code as well as decimal representation, etc.
|
|
|
Control Characters
|
ASCII codes before decimal 32... like bell, backspace and carriage return
|
|
|
ASCII Chart
|
Uppercase characters have different ASCII code than lowercase. Uppercase comes before lowercase. Numbers come before letters. Special characters spread around.
|
|
|
Extended ASCII
|
The 8 bit character chart is sometimes called this. Extra zero on the left.
|
|
|
Unicode
|
Another scheme developed so that many symbols in international languages may be represented. Also uses bit patterns like ASCII.
|
|
|
Integer
|
A whole number without a decimal portion. May be positive negative or zero. 2 categories: signed and unsigned.
|
|
|
Unsigned Integer
|
An integer without a sign, that is... a non negative integer. Range from zero to infinity. Is stored on RAM as it's value when represented as a binary number.
|
|
|
Overflow
|
When one tries to store a number in a memory location that is not large enough. May or may not receive an error message.
|
|
|
Maximum number storable in 1 byte
|
255
|
|
|
Sign and magnitude format
|
For signed integers. Used to allow positive and negative numbers and zero alike
|
|
|
Twos Complement
|
A format to use for negative number, still a sign and magnitude format... simply made for negative numbers. Used by switching 0s and 1s.
|
|
|
Unsigned integers
|
Stored as the binary number equivalent to the original
|
|
|
Signed positive integer
|
Stored using the sign and magnitude format where the magnitude is the binary equivalent
|
|
|
Signed negative integer
|
Stored using the sign and magnitude format where the magnitude is in the two's complement format
|
|
|
Floating point numbers
|
Represented using sign, exponent and mantissa (boring)
|
|
|
Sequence
|
Default control structure
|
|
|
The Structure Theorem
|
Sequence, selection and repetition have been shown to be enough control structures to write any computer program
|
|
|
Selection
|
Making a decision to execute several statements.. or not. Comparing one value with another and then making a decision from the comparison. Formed by a condition statement. If the condition is true one choice is selected. If it is false another choice is selected.
|
|
|
Condition statement
|
A statement that compares two values such that the result is true or false. Written as an If statement. Allows the algorithm and program to make a decision.
|
|
|
Comparison operators
|
> < = <= >= <>
|
|
|
Simple selection statement
|
A choice between two alternatives. If - then - else - endif.
|
|
|
Null else selection statement
|
Performs statements only when the condition is true. If - then - endif.
|
|
|
Combined selection statement
|
Multiple conditions using And and Or. If - and - then - endif. (Could use else)
|
|
|
Structured Programming
|
Indentation helps us see which statements are dependent on others. Using good programming style.
|
|
|
Control structures
|
Refer to the flow of control through the statements in our algorithms and programs
|
|
|
Repetition
|
When a set of statements are repeated forming a loop (multiple iterations of a block of code)
|
|
|
While loop
|
Repeats while a condition is true
|
|
|
For loop
|
Repeats a counted number of times
|
|
|
Sentinel value
|
A special input value that signals the end of a loop
|
|
|
Priming the loop
|
To set things up before the loop so the condition makes sense the first time it is tested (inputting a value to a variable, setting count to 0 etc)
|
|
|
Objects in Small Basic
|
objects containing predefined operations that are useful in many programs. are like toolboxes in which there are tools that are handy for lots of situations. Like text.converttouppercase etc.
|
|
|
Logic Error
|
An error found at desk check time for the algorithm or at run time for the program because it does not perform properly. Like an infinite loop.
|
|
|
Input validation
|
To check that what the user entered is legitimate and meaningful to the situation. Can use a While loop to do this.
|
