Hardware, Software, and Computer Languages Flashcards
Data that flows into the system
Input
Information that flows out of a system
Output
Activity that transforms the input into a more useful form
Processing
Used to keep data as it is processed or for later processing
Storage
Provides data to the computer
Input device
Not directly accessible to the CPU and used for long-term storage of computer programs and data
External memory
Executes the instructions of a computer program
CPU
Directly accessible to the CPU and used to store a computer program and its data while it is executing
Internal memory
Communicates information to external entities
Output devices
It stands for something else
Representation
It represents some thing in general terms and ignores its many concrete qualities
Abstraction
It represents a sequence of operations as a single task
Procedural abstraction
It represents the essential characteristics of data separated from its physical implementation
Data abstraction
Why do hardware and software engineers create abstractions?
To make devices easier to maintain, to make devices easier to use, and to allow user representations to have different implementations
A programmer uses a __________ to create his or her own procedural abstraction.
Method
A programmer uses a __________ to create his or her own data abstraction.
Class
A sequence of instructions written to perform some task
Computer program
A collection of related computer programs
Computer software
A data abstraction representing a location in the internal memory where a datum is stored
Variable
The process by which each machine instruction is fetched and executed in the order in which it appears in memory
Sequential execution
A hardware device that controls the flow of data through the CPU
Control unit
They transfer data from the internal memory to an output device or an external file
Output instruction
The process of converting alphanumeric characters into binary
Scanning
They transfer data from an input device or an external file into the computer’s internal memory
Input instructions
Determines the kind of values that can be stored into a variable
Data type
Sequences of zeroes and ones used to store data in the internal memory
Binary
The name by which you refer to a variable within a computer program
Identifier
Variable declaration
Informs the compiler of the variable’s data type and identifier
Expression
Tells the computer to perform calculations
Assignment statement
Stores a value into a variable
System.in
The standard input object
System.out.print
A method that sends data to the standard output object
Variable initialization
Gives the variable a starting value
How many variables can be declared and initialized within a single declaration statement?
Only one
What Java statement correctly declares x to be a double variable initialized to 3.5?
double x = 3.5;
What Java code fragment correctly inputs a floating-point value for x?
Scanner in = new Scanner( System.in ); double x = in.nextDouble( );
What Java code fragment correctly assigns 3 to feet and 36 to inches?
feet = 3; inches = 12 * feet;
Assuming variable x has value 3.5, what Java code fragment correctly prints x = 3.5 on a single output line?
System.out.print( “x = “ );
System.out.println( x );
An item in a language that is its smallest unit of meaning
Lexeme
The total inventory of words and symbols of a computer language
Lexicon
Its statements must describe how to get what you want as a result
Procedural language
Its statements must be broken into a sequence containing many machine operations
High-level language
A category of lexemes
Token
The compiler’s process of translating a program statement into equivalent machine code
Code generation
The compiler’s process of combining tokens into recognizable program statements
Syntax analysis
The compiler’s process of reading individual characters of a computer program and building its lexemes
Lexical analysis
The form of statements in a language
Syntax
The meaning of statements in a language
Semantics
Defined by those who implement Java’s libraries; its meaning is preset but it can be altered by the programmer
Predefined identifier
Message to the human reader that is ignored by the computer
Comment
Defined by those who created Java; its meaning is fixed and cannot be altered by the programmer
Keyword
Immutable program datum that stands for itself
Literal
Defined by a programmer for his or her own use
User identifier
For the following java fragment, what is the token class for ‘3.5’?
public static void main( String [] args ) {
double x = 3.5;
}
Literal
For the following java fragment, what is the token class for ‘String’?
public static void main( String [] args ) {
double x = 3.5;
}
Predefined identifier
For the following java fragment, what is the token class for ‘x’?
public static void main( String [] args ) {
double x = 3.5;
}
User identifier
For the following java fragment, what is the token class for ‘public’?
public static void main( String [] args ) {
double x = 3.5;
}
Keyword
Which of the following identifiers are spelled correctly?
first-quarter-sales
firstQuarterSales
1stQuarterSales
firstQuarterSaler
Which of the following keywords are spelled correctly?
double
Double
DOUBLE
double
Which of the following variable declarations are spaced correctly?
doubletaxRate=0.08;
double tax Rate = 0.08;
double taxRate=0.08;
double taxRate = 0 . 08;
double taxRate=0.08;
Tasks that the compiler and JVM must perform to support the translation and execution of a computer program
Housekeeping
Refers to anything that is created and can change during program execution
Dynamic
Program text that is primarily meant to provide information to the compiler
Declaration
Program statements that are primarily meant to specify operations that the computer is to carry out at runtime
Executable statement
Refers to anything that is created at compile time and stays fixed during the program run
Static
