deck_16987371 Flashcards
: the two major componentsof any computer system
Hardware and software
equipment, or devices
Hardware:
programs that contain instructions for thecomputer
Software:
allow data to enter thecomputer
Input devices:
working on the data
Processing:
hardware thatperforms the tasks
Central Processing Unit (CPU):
provide data to the user* Printer, monitor, speakers
output devices:
: special languagecontaining instructions for the compute
Programming language
rules governing word usage andpunctuation in the language
Syntax:
controls the computer’s on/offcircuitry
Machine language:
software that translatesprogramming languages to machine language
Compiler or interpreter:
Program must be free of ______________ to be run,or executed, on a compute
syntax errors
To function properly, the_______ must be correct
logic
are moredifficult to locate than syntax errors
Logic errors, or semantic errors,
a pictorial representation of thelogic steps
Flowchart:
Natural language representationof the logic
Pseudocode:
entire set of actions organizationmust take to switch over to new program(s)
Conversion:
Maintaining the Program
- Maintenance
- Making changes after the program is put into production
Understanding Interactive User Input
- Asks the user for a response
message displayed on a monitor
- Prompt:
location to type entries tocommunicate with the operating system
Command prompt:
allows usersto interact with a program in a graphicalenvironment
Graphical User Interface (GUI):
Input and output values
Input symbol
compute or action
Processing symbol
- Connect the steps
Flowlines:
Shows the start and end points of thestatements
Terminal symbol (start/stop symbol):*
a sequence of statements thatrepeats forever with no escape
Infinite loop:
testing a value
Decision:
Does not represent real data
Sentinel value (or dummy value)*
Code stored in the file that marks the end of thedata
End-of-file (EOF) marker:*
Marks a logic transfer to another location in theflowchart
Flowchart connector symbol:*
has an address and a value
Memory location:
is used for various operations
Value (contents)
Two basic data types
:* Text, Numeric
stored by numeric variables
Numeric data
stored by string, text, or charactervariables
Text data
:* Values that do not change while the program isrunning
Constants
Four major computer operations:*
Input
Processing
Output
Storage
Six programming phases:
- Understand the problem
- Plan the logic
- Code the program
- Translate the program to machine language
- Test the program
- Deploy the program
the equal (=) sign inmost languages
Assignment operator:
focuses on actionsperformed on data
Procedural programming:
focuses onrepresenting and manipulating objects
Object-oriented programming:
- All the text, numbers, and other information thatare processed by a computer
Data items
- Statement that provides a data type and anidentifier for a variable
Declaration
Variable’s name
Identifier
Declare a starting value for any variable
Initializing a variable
Variable’s unknown value before initialization
Garbage
- Specific numeric value
Numeric constant (or literal numeric constant)
String of characters enclosed within quotationmarks
String constant (or literal string constant)*
Do not have identifiers like variables do
Unnamed constants
- Can hold text* Letters of the alphabe
String variable
- Similar to a variable* Can be assigned a value only once* Assign a useful name to a value that will never bechanged during a program’s execution
named constant
- Unnamed constant* Purpose is not immediately apparent* Avoid this
Magic number
Standard arithmetic operators:
- (plus sign)—addition
- − (minus sign)—subtraction*
- (asterisk)—multiplication
- / (slash)—division
- Repeating input back to a user either in asubsequent prompt or in output
Echoing input
selection structure* Provides an action for each of two possibleoutcomes
Dual-alternative (or binary)
selection structure* Action is provided for only one outcome
Single-alternative (or unary)
Involves thinking in double negatives
“Not equal” operator
Using the wrong operator
Common errors
- Asks multiple questions before anoutcome is determine
Compound condition*
- Requires that both of two testsevaluate to true
AND decision
r Ask two or more questions in a single comparison
conditional AND operator
Describe the truth of an entire expression based onthe truth of its parts
Truth tables
Expression evaluated only as far as necessary todetermine truth
Short-circuit evaluation
Take action when one or the other of twoconditions is true
OR decision
Ask two or more questions in a single comparison
Conditional OR operator
compare a variable to a series of values betweenlimits
Range check
n requires that both conditionsbe true to produce a true result
AND decision
an AND decision, first ask the question thatis ___________
less likely to be true
requires that either of theconditions be true to produce a true result
An OR decision
In an OR decision, first ask the question that is
more likely to be true
Logically snarled program statements
Spaghetti code
Do not follow the rules of structured logic
unstructured programs*
Do follow rules of structured logic
Structured programs*
unit of programming logic
Structure Basic
Perform actions in order* No branching or skipping any task
Sequence
Repeat actions based on answer to a question
Loop
Perform actions inorder* No branching orskipping any task
Sequence
Situation where nothing is done
null case
Repeats a set of actions based on the answerto a question
Loop structure
Attaching structures end-to-end
stacking
Placing one structure within another* Indent the nested structure’s statements
Nesting
Group of statements that execute as a single unit
Block
Reads the first input data record
Priming read (or priming input)*
number of iterations predetermined* Also called counted loop
Definite loop:
numeric variable used to count numberof times an event occurs
Counter:
variable may be altered by userinpu
Loop control
: loop iterates until some conditionis true
Indefinite loop
any variable thatdetermines whether the loop will continue
Loop control variable:
loops within loops
Nested loops:
loop that contains the other loop
Outer loop:
loop that is contained
Inner loop:
variable that gathers values
Accumulator:
make sure data falls in acceptableranges
Validate data:
can be only true or false
Boolean expressions
are used when we want to execute a block of code repeatedly until some condition becomes true.
Looping statements
allows the program to repeat a set of instructions multiple times.
iteration statement
executes at least once, while the while loop may not execute if the initial condition is false.
The do…while loop
- Holds the action or actions that execute when
the tested condition in the decision is true
if-then clause
- Executes only when the tested condition in the
decision is false
else clause
Range check
* Compare a variable to a series of values between
limits
Range check
