CSCE 206 Ch. 1

portability

C++ program can be written on one type of computer and then run on many other types of systems

fetch/decode/execute cycle (CPU)

The CPU's control unit fetches, from main memory, the next instruction in the sequence of program instructions. The instruction is encoded in the form of a number. The control unit decodes the instruction and generates an electronic signal. The signal is routed to the appropriate component of the computer. The signal causes the component to perform the operation.

algorithm

a set of well-defined steps for performing a task or solving a problem. Steps are sequential.

address

a unique number assigned to each byte, they are ordered from lowest to highest

programmer

also called software developer. A person with the training and skills necessary to design, create, and test computer programs

object-oriented programming

centered on the object. object is a programming element that contains data and the procedures that operate on the data. it is a self -contained unit.

hardware components

central processing unit (CPU) main memory secondary storage devices input devices output devices

linker

combines the object file with the necessary library routines.

integrated development enviroments

consist of a text editor, compiler, debugger, and other utilities integrated into a package with a single set of menus.

executable file

contains machine language instructions, or executable code, and is ready to run on computer

control unit (CPU)

coordinates all of computer's operations. It is responsible for determining where to get the next instruction and regulating the other major components of the computer with control signals

Pseudocode

cross between human language and programming language. computer can't understand it but programmers find it helpful to write algorithm in language that's almost a programming language, but still very similar to natural language.

arithmetic and logic unit (CPU)

designed to perform mathematical operations

hierarchy chart

diagram that graphically depicts the structure of a program. Boxes used to show each step of program.

run-time library

extensive. programs almost always use some part of it. when the compiler generates an object file, however, it doesn't include machine code for any run-time library routines the programmer might have used

object file

if program is free of syntax errors, the compiler stores the translated machine language instructions, called object code, into file

syntax errors

illegal uses of key words, operators, punctuation, and other language elements

input devices

input is any info the computer collects from outside world. the device that collects the info and sends it to the computer is called an input device

compiler

it steps through the preprocessed source code, translating each source code instruction into the appropriate machine language instruction. uncovers any syntax errors

programming languages

low-level language is close to the level of a computer, which means it resembles numeric machine language of the computer more than the natural language of humans. high-level languages are closer to the level of human-readability than computer-readability.

punctuation

mark beginning or ending of a statement, or separate items in a list

disk drive

most common type of secondary storage. Stores data by magnetically encoding it into a circular disk

operating systems

most fundamental set of programs on a computer. the operating system controls the internal operations of the computer's hardware, manages all the devices connected to the computer, allows data to be saved to and retrieved from storage devices, and allows other programs to run on the computer

variable

named storage location in the computer's memory for holding a piece of info. Info stored here may change while program is running

byte

one byte is enough memory to store only a letter of the alphabet or a small number. In order to do anything meaningful, a computer must have lots of bytes.

output devices

output is any info the computer sends to the outside world. Info is sent to output device which formats and presents it

operators

perform operations on one or more operands. an operand is usually a piece of data, like a number

utility programs

performs a specialized task that enhances the computer's operation or safeguards data. examples of utility programs are virus scanners, file-compression programs, and data-backup programs

C++

popular because of its mixture of low and high level features and its portability.

procedural programming

programmer constructs procedures. the procedures are collections of programming statements that perform specific task. procedures each contain their own variables and commonly share variables with other procedures. centered on procedure, or function

system software

programs that control and manage the basic operations of a computer

application software

programs that make a computer useful for everyday tasks. these are the programs that people normally spend most of their time running on their computers.

preprocessor

reads the source code. it searches for special lines that begin with the # symbol. lines contain commands that cause preprocessor to modify the source code in some way

syntax

rules that must be followed when constructing a program. Syntax dictates how key words and operators may be used, and where punctuation symbols must appear.

program

set of instructions that a computer follows to perform a task. Referred to as software. Software is essential to a computer because without software, a computer can do nothing

source file

source code, or the statements written by a programmer are saved in this file

bit

stands for binary digit. they are tiny electrical components that can hold either a positive or negative charge. Positive charge is thought of as switch in the "on" position and negative charge as switch in the "off" position

CPU

the part of the computer that actually runs programs. most important part of computer because without it, the computer could not run software

hardware

the physical components that a computer is made of. A computer is made of different parts

desk-checking

the programmer starts reading the program, or a portion of the program, and steps through each statement. by stepping through each statement, many errors can be located and corrected

software development tools

the software tools that programmers use to create, modify, and test software.

USB drives

they are small devices that plug into the computer's USB (universal serial bus) port, and appear to the system as a disk drive. They use flash memory to store data.

secondary storage

type of memory that can hold data for long periods of time even when there is no power to the computer.

variable definition

used to define one or more variables that will be used in the program, and to indicate the type of data they will hold.

main memory

where the computer stores a program while the program is running, as well as the data that the program is working with. Also known as random-access memory (RAM). Called this because the CPU is able to quickly access data stored at any random location in RAM. It is usually volatile type of memory that is used only for temporary storage while program is running.

programmer-defined identifiers

words or names defined by programmers. They are symbolic names that refer to variables or programming routines

key words

words that have a special meaning, they may only be used for their intended purpose. Also known as reserved words