memory location in c++

8/18/2019 Memory Location in C++

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Inside every computer is a componentcalled internal memory.

Computer’s internal memory is composedof memory locations, each with a uniquenumeric address.

Memory location is similar to collection ofstorage bins.

Each address can store one item at a time.

Internal Memory


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Illustration of Storage Bins


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Memory Location

Data Type ' indicates what type ofinformation the address will store %e.g.,

numeric or te!tual&. Identifer ' allows the programmer to

refer to the memory location elsewhere

in the program.' (ames made up by the programmer.


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"ypes of Identi$er

Variables - are memory locations whosevalues can change during runtime %when theprogram is running&. Most memory locationsare variables.

Constants ' are memory locations whosecontent cannot be changed during programe!ecution. )ften named in uppercase letters.

E!ample* PI %constant&, radius %variable&


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+ules In (aming Identi$ers%variables&

(ame must begin with a letter and containonly letters, numbers, and the underscorecharacter

(o punctuation mars, spaces, or other specialcharacters %such as - or & are allowed

Cannot be a eyword %word that has specialmeaning in C//&

(ames are case sensitiveE!ample* discount is di0erent from DISCOUNT andfrom Discount


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1alid or Invalid 1ariables

total2ales

"otal32al4s

"otal 2ales total.2ales

5th6tr2ales total2ale-

"7taLsales


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C// 8eywords

8eywords are prede$ned reservedwords or reserved identi$ers that

have special meanings. "hey cannot be used as identi$ers in

your program


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C// 8eywords

auto

constdouble

9oat

brea

continueelse

for

void

case

default

char


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C// 8eywords

int

shortstruct

endl

long

signedunsigned

e!plicit

do

while

bool

string


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#ata "ypes

Memory locations come in di0erenttypes and si:es

memory location will only accept anitem that matches its data type.

#ata type of a memory location isdetermined by the programmer whendeclaring the location.


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short

int

float double

bool

char string (user-defned data type)

;undamental #ata "ypes in C//


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bool ' stores


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;undamental #ata "ypes in C/

/ oat and double - store real numbers

%numbers with a decimal place&

#i0erences are range of values, precision,and memory used %double has the greaterof each&

char ' stores characters %letter, symbol,or number that will not be used in acalculation& )nly one character stored at a time


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;undamental #ata "ypes in C

/ strin - is a user'de$ned data type,

can store :ero %blan& or more

characters


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#eclaring Memory Location

>hen declaring a memory location a data type andan identi$er %variable or constant& must be provided

2ynta! for declaring a variable in C//

DataType Identifier ; !"amples#

string age;

float length;

int width;

string lastname;


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ssigning ;loating'point 1aluesto Integer 1ariables

If a 9oating'point value is assigned to aninteger variable "he fractional part will be truncated %i.e.,

?chopped o0@ and discarded& "he value is not rounded

int rainfall = 3.88;cout


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2tring Literals

Can store a series of characters inconsecutive memory locations.

"Hello"

Enclosed in a double quotation " "

Can de$ne string data type in programs string nae;


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char $s strin literal constants

Character literal constants initiali:e char data types Consist of one character in single quotation

mars

2tring literal constants initiali:e string datatypes

Aero or more characters enclosed in doublequotation mars Empty string %“ ”& is a valid string literal

constant.


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+eading in a 2tring 2tatement

' +eads in a string with no blansstring nae;

cin !! nae;

' +eads in a string that may contain blansstring nae;

getlinecin# nae$;


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8nowledge Chec

Identify the data type of the following variables*!astname

PI where PI #$%&%'

( where ( %))

*adius where radius +,

True

width where width %)

-gePhoneNum.er

)


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repared by* rof. L+6 (atividad

Than% & ou''

That in ll Thins od May ,e lori

memory location in c++

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