Chapter 2 - Simple C++ Programs

8/17/2019 Chapter 2 - Simple C++ Programs

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Copyright © 2012 Pearson Education, Inc.

Chapter 2

Simple C++ Programs


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Outline

O!ecti"es1. C++ Program Structure

2. Constant and #ariales

$. C++ Classes

%. C++ Operators

&. Standard Input and Output

'. (uilding C++ Solutions )ith I*Es

. (asic unctions in C++ Standard -irary

. Prolem Sol"ing /pplied

. System -imitations


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O!ecti"es

*e"elop prolemsol"ing solutions in

C++ containing

3Simple arithmetic computations

3 In4ormation printed on the screen

3 5sersupplied In4ormation 4rom 6eyoard

3 Programmerde4ined data types


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C++

ProgramStructure

/*--------------------------------------------------------

* Program chapter1_1

* This program computes the distance between two points.

*/

#include // Reuired !or cout" endl.

#include // Reuired !or srt$

using namespace std%

int main$ &

// 'eclare and initiali(e ob)ects.

double 11$" +1,$" $" +$"

side1" side" distance%

// 0ompute sides o! a right triangle.

side1 - 1%

side + - +1%

distance srtside1*side1 2 side*side$%

// Print distance.

cout


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/*--------------------------------------------------------



*/




int main$ &


double 11$" +1,$" $" +$"



side1 - 1%

side + - +1%


// Print distance.

cout


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/*--------------------------------------------------------



*/




int main$ &


double 11$" +1,$" $" +$"



side1 - 1%

side + - +1%


// Print distance.

cout


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/*--------------------------------------------------------



*/




int main$ &


double 11$" +1,$" $" +$"



side1 - 1%

side + - +1%


// Print distance.

cout


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/*--------------------------------------------------------



*/




int main$ &


double 11$" +1,$" $" +$"



side1 - 1%

side + - +1%


// Print distance.

cout


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/*--------------------------------------------------------



*/




int main$ &


double 11$" +1,$" $" +$"



side1 - 1%

side + - +1%


// Print distance.

cout


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/*--------------------------------------------------------



*/




int main$ &


double 11$" +1,$" $" +$"



side1 - 1%

side + - +1%


// Print distance.

cout


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/*--------------------------------------------------------



*/




int main$ &


double 11$" +1,$" $" +$"



side1 - 1%

side + - +1%


// Print distance.

cout


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Constants

and

#ariales



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Constants and #ariales

3 Constants and "ariales represent memory locations that

)e re4erence in our program solutions.

3 Constants are o!ects that store speci4ic data that can not e

modi4ied.

– 10 is an integer constant

– 4.5 is a 4loating point constant

– "The distance between the two points is" is a string

constant

FaF is a character constant

3 #ariales are named memory locations that store "alues that can be

modified.

– double x1(1.0), x2(4.5), side1;

– side1 = x2 x1;

– x1, x2 and side1 are eGamples o4 "ariales that can e modi4ied.



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Initial #alues

3 C++ does not pro"ide initial "alues

4or "ariales.

@hus using the "alue o4 a "ariale e4ore it is

initialiBed may result in =garage7.



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Aemory Snapshots

3 Aemory =snapshots7 are diagrams that

sho) the types and contents o4 "ariales

at a particular point in time.



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#alid C++ Identi4iers

3 Aust egin )ith an alphaetic

character or the underscore character =H7

3 /lphaetic characters may e either upper or

lo)er case. C++ is C/SE SESI@I#E, so =a7 JK =/7, etcL

3 Aay contain digits, ut not in as the 4irst character.

3 Aay e o4 any length, ut the 4irst $1 characters

must e uniMue.

3 Aay O@ e C++ 6ey)ords.



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C++ Ney)ords



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C++ Identi4iers

3 Should e care4ully chosen to re4lect

the contents o4 the o!ect.

@he name should also re4lect the units o4

measurements )hen applicale.

3 Aust e declared >and there4ore typed?

e4ore they may e used.

C++ is a strongly typed programming

language.



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Common C++ *ata @ypes

3 Ney)ord EGample o4 a constant

– bool t!ue

– cha! 5

– int 25

– double 25.0

– st!in# "hello"

99$include%st!in#&



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*eclarations

3 / type declaration statement de4inesne) identi4iers and allocates memory.

3 /n initial "alue may e assigned to a memory

location at the time an identi4ier is de4ined.


Syntax[modifier] type specifier identifier [= initial value];[modifier] type specifier identifier[(initial value)];

EGamples

double 1" +15$%int counter5%const int 789_:8;45%bool error!alse$%char comma"$%


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Symolic Constants

3 / symolic constant is de4ined in a declaration

statement using the modi4ier const.

3 / symolic constant allocates memory 4or an

o!ect that can not e modi4ied duringeGecution o4 the program. Any attempt to

modify a constant will be flagged as a syntax

error by the compiler .

3 / symolic constant must e initialiBed in the

declaration statement.



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C++ Classes



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Class *eclarations

3 Speci4y a programmerde4ined type9o!ect.

3 (egin )ith 6ey)ord =class7 4ollo)ed y the

name >i.e. identi4ier? o4 the type.

Class de4inition is made in a code loc6.

Class memers may include data >attriutes?

and methods >4unctions?.

#isiilities o4 public , protected , and private are used to control access to class memers

/ semicolon must 4ollo) the closing rac6et D



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Class Aethods

3 *e4ine the operations that can eper4ormed on class o!ects.

/ constructor is a special method that is eGecuted

)hen o!ects o4 the class type are created

>instantiated ?. Constructors must ha"e the same name as the class.

/ class may de4ine multiple constructors to allo)

greater 4leGiility in creating o!ects.

3 @he de4ault constructor is the one that has no parameters.3 ParameteriBed constructors pro"ide initial "alues o4 data

memers.



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Class *e4initions

3 O4ten declared in t)o parts

@he class declaration is typically )ritten in a 4ile

named =classame.h7

3 *e4ines the class including data memers and theheaders o4 the class methods.

@he implementation o4 class methods is

typically )ritten in a 4ile named

=classame.cpp7

3


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Class SyntaG



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5sing a Class

3 Once a class is de4ined, you may use

the class as a type speci4ier.

Rou must include the class de4inition >i.e. header 4ile?



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C++ Operators



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/ssignment Operator

3 @he assignment operator >K? is used

in C++ to assign a "alue to a memory

location.

3 @he assignment statementx1 = 1.0;

assigns the "alue 1.0 to the "ariale x1.

@hus, the "alue 1.0 is stored in the memorylocation associated )ith the identi4ier x1.

>ote x1 must ha"e een pre"iously declared.?



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Order o4 @ypes

3 (ecause di44erent types are

di44erent

representations, 4reMuently )e

need to con"ert et)een types. Sometimes these con"ersions may

loose in4ormation.

Con"ersion 4rom lo)er types to higher

types results in no loss o4 in4ormation. Con"ersion 4rom higher types to lo)er

types may loose in4ormation.


igh!

"ow!

long doubledoublefloat

long integer integer short integer


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/ssignment Statements

Assignment operators must not be

confused with equality.



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/rithmetic EGpressions

3 EGpressions appearing in assignment

statements 4or numeric "ariales may e

simple literals >e.g. x1 = 10.4;?, reading

the "alue stored in a "ariale >e.g. x2=x1;?, or e more compleG eGpressions

in"ol"ing the e"aluation o4 one or more

operators >e.g. x1 = '.4x2 10.4?.



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/rithmetic Operators

3 /ddition #

3 Sutraction $

3 Aultiplication %

3 *i"ision &3 Aodulus '

Aodulus returns remainder o4 di"ision et)een t)o

integers

EGample' returns a "alue o4 1



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Operator (asics

3 @he 4i"e operators >: 9 + ? are

binary operators operators that reMuire

t)o arguments >i.e. operands?.

3 C++ also include operators that reMuire

only a single argument unary

operators.

or eGample, a plus or a minus sign

preceding an eGpression can e unary

operators >e.g. x2?.



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Integer *i"ision

3 *i"ision et)een t)o integers results

in an integer.

3 @he result is truncated, not rounded

3 EGample

@he eGpression &* e"aluates to 1

@he eGpression *&+ e"aluates to 0



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AiGed Operations

3 (inary operations on t)o "alues o4

same type yield a "alue o4 that type >e.g.

di"iding t)o integers results in an integer?.

3 (inary operations et)een "alues o4

di44erent types is a mixed operation.

#alue o4 the lo)er type must e con"erted to

the higher type e4ore per4orming operation.

Tesult is o4 the higher type.



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Casting

3 @he cast operator.

@he cast operator is a unary operator that reMuests

that the value o4 the operand e cast, or changed, to

a ne) type 4or the neGt computation. ,he type of the

operand is not affected-

3 EGampleint count>10?, sum>&&?

doule a"eragea"erage K >doule?sum9count


Memory snapshot:

int count

int sum

double average

10

&&

&.&


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O"er4lo) and 5nder4lo)

3 O"er4lo) ans)er too large to storeEGample using 1' its 4or integers!esult = '2000 5'2;

3 EGponent o"er4lo) ans)er7s eGponent is too largeEGample using 4loat, )ith eGponent range $ to $!esult = '.25e2* 1.0e15;

3 EGponent under4lo) ans)er7s eGponent too smallEGample using 4loat, )ith eGponent range $ to $!esult = '.25e2* 1.0e15;


I t d * t


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Increment and *ecrement

Operators3 Increment Operator ##

3 post increment x##;

3 pre increment ##x;

3 *ecrement Operator $ $3 post decrement x$ $;

3 pre decrement $ $x;

3 or eGamples assume 6K& prior to eGecuting the

statement.3 mK ++6 99 oth m and 6 ecome '

3 n K 6 99 n ecomes & and 6 ecomes %


/ i t d / i t


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/re"iated /ssignment

Operators

operator example e.uivalent statement

= x+=2; x=x2;

= x-=2; x=x2;

= x*=y; x=x+;

= x/=y; x=x+;-= x%=y; x=x-+;



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Operator Precedence


/recedence 0perator Associativity

1 Parenthesis >? Innermost irst

2 5nary operators+ ++ >type? Tight to le4t

$ (inary operators: 9

-e4t to right

% (inary operators+

-e4t to right

& /ssignment OperatorsK +K K :K 9K K

Tight to le4t


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Standard Input 9 Output



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Sample Output cout

cout is an ost!ea/ o!ect, de4ined in the header4ile iost!ea/

cout is de4ined to stream data to standard output

>the display? e use the output operator UU )ith cout to

output the "alue o4 an eGpression.

;eneral ormcout 11 eGpression 11 eGpression;

2ote! An expression is a 3## constant4 identifier4 formula4 or functioncall-



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Simple Input cin

cin is an ist!ea/ o!ect de4ined

in the header 4ile iost!ea/

cin is de4ined to stream data 4rom standard input

>the 6eyoard?

3 Ve use the input operator && )ith cin to assign

"alues to "ariales

;eneral ormcin && identifier && identifier ;

3 2ote! 5ata entered from the 6eyboard must be compatible with the data

type of the variable-



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Characters and Input

3 @he input operator WW s6ips all)hitespace characters.

3 @he get>? method gets the neGt character.

3 EGampleint G

char ch

cin WW G WW chcin WW G

cin.get>ch?


Input stream:

45 c

39

b

Memory Snapshot

x ch

x ch

45 ‘c’

39 ‘\n ’


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Aanipulators and Aethods

3 endl places a ne)line character in the outputu44er and flushes the buffer.

3 set4>? and unset4>?


lag Aeaning

iossho)point display the decimal pointios4iGed 4iGed decimal notation

iosscienti4ic scienti4ic notation

Ios::setprecision>n? set the numer o4 signi4icant digits to e printed to theinteger "alue n

Ios::set)>n? set the minimum numer o4 columns 4or printing theneGt "alue to the integer "alue n

iosright right !usti4ication

iosle4t le4t !usti4ication

( ildi C++ S l ti


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(uilding C++ Solutions

)ith I*Es


I t t d * l t


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Integrated *e"elopment

En"ironments >I*Es?3 I*Es are so4t)are pac6ages designed

to 4acility the de"elopment o4 so4t)are

solutions.

3 I*Es include Code editors

Compiler

*eugger @esting tools

Aany additional help4ul toolsL


( i ti i C++


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(asic unctions in C++

Standard -irary


(asic C++ Aath


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(asic C++ Aath

unctions


abs!"# computes absolute value o "

s$rt!"# computes s$uare root o "% &here" '()

po&!"%y# computes "y

ceil!"# nearest integer larger than "

loor!"# nearest integer smaller than "

e"p!"# computes e"

log!"# computes ln "% &here " ')

log*)!"# computes log*)"% &here "')


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@rigonometric unctions


sin!"# sine o "% &here " is in radians

cos!"# cosine o "% &here " is in radians

tan!"# tangent o "% &here " is in radians

asin!"# +his unction computes the arcsine% or inverse sine% o "% &here "must be in the range ,-*% *./

+he unction returns an angle in radians in the range ,-012% 012./

acos!"# +his unction computes the arccosine% or inverse cosine% o "%&here " must be in the range ,-*% *./

+he unction returns an angle in radians in the range ,)% 0./

atan!"# +his unction computes the arctangent% or inverse tangent% o "/


atan2!y%"# +his unction computes the arctangent or inverse tangent o thevalue y1"/


Common unctions


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Common unctions

*e4ined in UcctypeW


isalpha!ch# eturns true i ch is an upper or lo&er case letter/

isdigit!ch# eturns true i ch is a decimal digit

isspace!ch# eturns true i ch is a &hitespace character/

islo&er!ch# eturns true i ch is an lo&er case letter/

isupper!ch# eturns true i ch is an upper case letter/

tolo&er!ch# eturns the lo&ercase version o ch i ch is an uppercasecharacter% returns ch other&ise/

toupper!ch# eturns the uppercase version o ch i ch is a lo&ercasecharacter% returns ch other&ise/


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Prolem Sol"ing /pplied


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System -imitations



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Documents

Chapter 2 - Simple C++ Programs