CS 101 Exam 1

fetch-decode-execute cycle

1. Fetch. A program is a long sequence of machine language instructions. The first step of the cycle is to fetch, or read, the next instruction from memory into the CPU.2. Decode. A machine language instruction is a binary number that represents a command that tells the CPU to perform an operation. In this step the CPU decodes the instruction that was just fetched from memory, to determine which operation it should perform.3. Execute. The last step in the cycle is to execute, or perform, the operation.

syntax error

An error that results when an instruction does not follow the syntax rules or grammar of the programming language.

Unicode

An extensive encoding scheme that can represent the characters of many of the language in the world is

output devices

Devices that enable the computer to give the user the results of the processed data. (ex. video displays and printers)

order of operations

PEMDAS

microprocessor

The central processing unit that is generally made from a single integrated circuit.

processor

The component of a computer that follows instructions

statements

The individual instructions that you write a program in a high-level programming language

machine language

The language made up of binary-coded instructions that is used directly by the computer

bit (binary digit)

a byte is made up of 8 of them

byte

a computer's memory is divided into tiny storage locations known as ___. One is only enough memory to store a letter of the alphabet or a small number.

camelCase

a convention for naming variables that capitalizes the first letter of every word without spaces

hand tracing

a debugging process where you imagine that you are the computer executing a program, also known as desk checking

flowchart

a diagram that graphically depicts the steps that take place in a program

control structure

a logical design that controls the order in which a set of statements executes

logic error

a mistake that does not prevent the program from running, but causes it to produce incorrect results

named constants

a name that represents a value that cannot be changed during the program's execution, written in all uppercase letters

numeric literal

a number that's written into a program's code

programmer / software developer

a person with the training and skills necessary to design, create, and test necessary computer programs

interpreter

a program that both translates and executes the instructions in a high-level language program

complier

a program that translates a high-level language program into a separate machine language program

math operators

a programmer's tools for performing calculations

strings

a sequence of characters that is used as data

ASCII

a set of 128 numeric codes that represent the English letters, various punctuation marks, and other characters

program

a set of instructions that a computer follows to perform a task

syntax

a set of rules that must be strictly followed when writing a program, dictates how key words, operators, and various punctuation characters must be used in a program

sequence structure

a set of statements that execute in the order that they appear

algorithm

a set of well-defined logical steps that must be taken to perform a task

connector symbol

a small circle with a letter written inside it, used to connect flowcharts side by side on a page

variable

a storage location in memory that is represented by a name

integrated development environments (IDE)

a text editor that has specialized features for writing statements in a high-level programming language, a compiler/interpreter, useful tools for testing programs and locating errors

secondary storage

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

uninitialized variable

a variable that has been declared, but has not been init

high-level language

allows you to create powerful and complex programs without knowing how the CPU works and without writing large numbers of low-level instructions

digital device

any device that works with binary data

internal documentation

appears as comments in a program's code

low-level language

assembly language, close in nature to machine language

initialization

assigning a value to a variable in the declaration statement

binary numbers vs. decimal (base 10) numbers

binary numbers have two numbers to store data vs decimals don't

line comments

comments that occupy a single line, and explain a short section of the program

main memory (RAM)

computer's work area, where a computer stores a program while the computer is running, as well as the data that the program is working with

off-page connector symbol

connects pieces of a flowchart on separate pages, shaped like home plate

digital data

data that is stored in binary

IPO chart

describes the input, processing, and output of a program

program development cycle

design the program, write the code, correct syntax errors, test the executable code, debug the code

input devices

enable the user to input data and commands into the computer (ex. keyboard, mouse, touchscreen...)

pseudocode

fake code, an informal language that has no syntax rules, and is not meant to be compiled or executed

pixels

images are composed of tiny dots of color known as ______.

IPO

input, processing, output

keywords or reserved words

language has its own set of words that the programmer must learn in order to use the language

prompt

message that tells (or asks) the user to enter a specific value

two's complement

negative numbers are encoded using this technique

instruction set

operations that are typically understood only by microprocessors of the same brand.

terminal symbols

ovals, used for the start and the end of the program

output symbols

parallelograms, displays data to user

input symbols

parallelograms, prompts user for data

CPU

part of the computer that actually runs programs, small chips known as microprocessors

operators

perform various operations on data

running/executing a program

performing program instructions on given data

math expression

performs a calculation and gives a value

software

programs are referred to as this, without it a computer can do nothing

user-friendly

programs that are easy to use

system software

programs that control and manage the basic operations of a computer

application software

programs that make a computer useful for everyday tasks, programs that people normally spend most of their rime running on their computers

Constant

pseudocode for named constant

Display

pseudocode, displays a line of text to the user

Declare

pseudocode, lists variable names

Input

pseudocode, tells the user to input some kind of data

Set

pseudocode, used to pair a variable with a number or equation

ROM

read-only memory, a computer can read the contents, but cannot change its contents or store additional data there

floating-point notation

real numbers are encoded using this

processing symbols

rectangles

hardware

refers to all the physical devices or components that a computer is made of

comments

short notes placed in different parts of a program, explaining how those parts of the program work

assignment statement

statement that sets a variable to a specified value

variable declaration

statement that specifies a variable's name and data type

block comments

take up several lines and are used when lengthy explanations are required

debug

the programmer finds and corrects the code that is causing the logic error

source code

the statements that a programmer writes in a high-level language

data type

the type of data that the variable will hold

operands

the values on the right and left of the operator

external documentation

typically designed for the user, contains documents such as a reference guide that describes the program's features and tutorials that teach the user how to operate the program

assembler

used to translate an assembly language program to a machine language program

assembly language

uses short words known as mnemonics instead of binary numbers for instruction

String

variable that holds any string of characters

Integer

variable that holds whole numbers

Real

variable that holds whole numbers or numbers with a fractional part

volatile versus nonvolatile

volatile will lose contents when a computer is shut off, nonvolatile won't

string literals

when a string appears in the actual code of the program

integer division

when an integer is divided by an integer, the result will also be an integer

mnemonics

written instead of binary numbers when using assembly language to write a program