MELJUN Intro to C++ Programming

8/14/2019 MELJUN Intro to C++ Programming

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Introduction To C++Introduction To C++Programming LanguageProgramming Language

LECTURE MELJUN CORTES, MBA,MPAMELJUN CORTES,

MBA,MPA


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What is C++

C++ is a high-level language and itis evolved from C over a period ofseveral years starting in 1980.

The standard for C++ was jointlydeveloped by the American NationalStandards Institute (ANSI) and the

International Standards Organization(ISO).

a set of rules, symbols, and special

words used to construct a computer


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Structure of a C++ Program

Figure 3.1 Structure of a C++ Program


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A Typical C++ Program

// A typical C++ Program

# include

using namespace std;

# define PI 3.142

int Integer;

int main ( )

{

double radius, area;

radius = 7;

area = radius * radius * PI;

return 0;

}

Preprocessor Directive

Comment

Main

function

Global Declaration

Local declaration

Statements


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Token

Token : combination of the characters in C++

Categorised into:

Identifiers Reserved words/keywords

Constants

Literal String

Punctuators Operators


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Identifiers

Allows programmers to name data and other objects in theprogram-variable, constant, function etc.

Can use any capital letter A through Z, lowercase letters athrough z, digits 0 through 9 and also underscore ( _ )

Rules for identifier The first character must be alphabetic character orunderscore

It must consists only of alphabetic characters, digits andunderscores, cannot contain spaces

It cannot duplicate any reserved word C++ is case-sensitive; this means that CASE, Case, case,

and CaSe are four completely different words.


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Valid and Invalid Identifiers

Valid names

Astudent_name_aSystemNam

e

pialstdntNm_anthrSysNmPI

Invalid names

$sum // $ is illegal2names // cant start with

2stdnt Nmbr // cant have

space int // reserved word


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Reserved word/Keywords

A word that has special meaning inC++.

Keywords cannot be used to nameidentifiers.


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Constant

Data values that cannot be changedduring the execution of a program

Types of constant: Literals constantDefined constantsDeclared constants


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Literals Constant

If the data cannot be changed, we can simply codethe data value itself in a statement

Eg: discount = 0.10 ;

Categorised into: Integer Numerals ( eg: 178, -9, 0113, 0x4b)Floating-Point Numerals (eg: 3.14159,6.02e23,1.6e-19 ,3.0

Characters ( eg: A, p)

Strings ( eg; Hello World)

Boolean (eg: true , false).

0.10 is a literalconstant


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Defined Constant (#define)

Use the#define preprocessor directive Format: #define identifier value

Eg : #define EPF_RATE 0.11 Placed at the beginning of the program

#include using namespace std;#define EPF_RATE 3.142

int main(){

;nett = salary ( salary * EPF_RATE);;

}


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Declared Constants

se a type const qualifier to indicate that datacannot be changed and to fix the contents of

the memory location

g: const float pi = 3.1416;

eclared inside a function

#include using namespace std;#define EPF_RATE 3.142

int main(){

const double socso_rate = 0.05;nett = salary ( salary * EPF_RATE * socso_rate);;

}


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Data Types in C++

Type defines a set of value and operationsthat can be applied on those values

Set of values for each type is known as thedomain for the type

Functions also have types which is

determined by the data it returns


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Data Types

Standard

They serves as the basic building blocks for derivedtypes (complex structures that are built using thestandard types

Serves as the basic building blocks for derived types


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Data Types

Derived


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Data Type : Void

Typed as void Has no values and operations Both set of values are empty Usually used in functionsEg: void printSum()


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Data Type : Char

Used to hold characters or very smallinteger values

Usually 1 byte of memory CODE:

char letter;

letter = 'C';


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Data Type : Integer

Coded as int A number without a fraction part C++ supports three different sizes of

integershort intintlong int

Can be signed and unsigned


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Data Type : Integer

Type Byte Size MinimumValue

Maximum Value

short int 2 -32,768 32,767

unsigned short int 2 0 65,535

int 4 -2,147,483,648 2,147,483,647

unsigned int 4 0 4,294,967,295

long int 4 -2,147,483,648 2,147,483,647

unsigned long int 4 0 4,294,967,295


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Data Type : Float

A number with fractional part such as 43.32, - 2.33

C++ supports three types of float

floatdouble

long float Stored in a form similar to scientific notation Can be represented in Fixed point (decimal) notation:

31.4159 0.0000625E notation:

3.14159E1 6.25e-5


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Data Type Float

Are double by default Can be forced to be float (3.14159f) or

long double (0.0000625L)

All floating-point numbers are signed

Type Byte Size Precision Range

float 4 7 10-37 ..1038

double 8 15 10-307 ..10308

long double 8 15 10-307 ..10308


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Data Type : Boolean

Represents values that are true or false

bool variables are stored as small integers

falseis represented by 0,

trueby 1:

bool allDone = true;

bool finished = false;

allDone finished

0


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Variables

A storage location in memory whose contents can change whileprogram is running

Has an identifier and a type of data it can hold

Variable declaration syntax :

type identifier [= initial_value]

eg : int itemsOrdered;

A variable name should represent the purpose of the variable.To hold the number of items

ordered.


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Variables


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Variables Assignment

An assignment statement uses the = operator tostore a value in a variable.item = 12;

This statement assigns the value 12 to the itemvariable.

The variable receiving the value must appear onthe left side of the = operator.

This will NOT work: // ERROR!12 = item;


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Variables Scope

The scope of a variable: the part of the programin which the variable can be accessed

A variable cannot be used before it is defined


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Variables Scope

Global Variables

Local Variable

Local Variable


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Variables Scope

Global scope a global variable is a variable declared in the main

body of the source code, outside all functions

Global variables can be referred from anywhere in the

code, even inside functions, whenever it is after itsdeclaration.

Local Scopea local variable is one declared within the body of a

function or a block. is limited to the block enclosed in braces ({}) where

they are declared.


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Operators

C ++ uses a set of built in operators ( Eg : +,-, / etc).

Four classes of operators :

ArithmeticRelationalLogical

Assignment


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Arithmetic Operators

Assume int a=4, b= 5, d;

C++

Operation

Arithmetic

Operator

C++

Expression

Value of d

after

assignmentAddition + d = a + b 9

Substraction - d = b - 2 3

Multiplication * d = a * b 20

Division / d = a/2 2

Modulus % d = b%3 2


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Assignment Operators

Assume x=4, y=5, z=8;Assignment

Operator

Sample

Expression

Similar

Expression

Value of variable

after assignment

+= x += 5 x = x + 5 x=9

-= y -= x y = y - x y=1

*= x *= z x = x*z x=32

/= z /=2 z = z/2 z = 4

%= y %=x y = y%x y=1

R l ti l & E lit


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Relational & EqualityOperators Assume y = 6, x =5

Relational Operators Sample Expression Value

> y > x T

< y < 2 F

>= x >= 3 T


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Logical Operators

Logical Operators Called Sample Operation

&& AND expression1 && expression 2

| | OR expression1 | | expression2

! NOT !expression

Example :Assume int x = 50

expression !expression Sample Expression

F T !(x == 60)

T F !(x != 60)


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Logical Operators

Assume x=4, y=5, z=8

expression1 expression2 expression1 &&

expression2

Sample Expression

F F F ( y > 10) && ( z


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Increment and DecrementOperators

Operator Called Sample

Expression

Similar

Expression

Explanation

++ preincrement ++a a = a +1

a += 1

Increment a by 1, then use

the new value of a in

expression in which a reside

++ postincrement a++ a = a +1

a += 1

Use the current value of a in

the expression which a

reside, then increment a by

1

- - predecrement - - a a = a -1

a -= 1

Decrement a by 1, then usethe new value of a in

expression in which a reside

- - postdecrement a - - a = a -1

a -= 1

Use the current value of a in

the expression which a

reside, then decrement a by1


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Operator Precedence

Operators Associative

( ) Left to right

++ - - + - ! Right to left

* / % Left to right

+ - Left to right

< >= Left to right

= = != Left to right

&& Left to right

| | Left to right

*= += - = /= %= Right to left


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Operator Precedence

Example 1:

int a=10, b=20, c=15, d=8;

a*b/(-c*31%13)*d

1. a*b/(-15*31%13)*d

2. a*b/(-465%13)*d

3. a*b/(-10)*d

4. 200/(-10)*d5. -20*d

6. -160

Example 2:

int a=15, b=6, c=5, d=4;

d *= ++b a/3 + c

1. d *= ++b a/3+ c

2. d*=7- a/3+c

3. d*=7- 5+c

4. d*=2 + c5. d*= 7

6. d = d*7

7. d = 28


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Example of a program

// Operating with variables#include


int main(){

//variables declarationint no1;int no2;

int value_div;int value_mod;

cout > no1 >> no2;value_div= no1 / no2;

cout


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/ Evaluate two complex expression /

#include


void main ( )

{

int a =3, b=4, c = 5, x, y;

cout


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Formatting Output

Output is made more readable usingmanipulator

Must include header file.Manipulators Use

endl

dec

oct

hex

fixedshowpoint

setw()

setprecision

setfill()

New line

Formats output as decimal

Formats output as octal

Formats output as hexadecimal

Set floating-point decimalsShows decimal in floating-point values

Sets width of output fields

Specifies number of decimals for floating point

Specifies fill character


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Formatting Output

Set Width (setw) Set the minimum width for an outputTwo alignment : right justified and left

justified Set Fill Character (setfill) If the output width is greater than the data

values placed in it, a fill character can be

used to fill the empty spaces wheneverrequired


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Formatting Output

Three integer manipulators:Decimal (dec)The default

Value in decimal form Octal (oct) Values are displayed in octal numbering system

Hexadecimal (hex) Values are in hexadecimal format


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Formatting Output

Three Floating-point manipulators: Fixed (fixed)

Displays floating-point numbers (eg:1.234568e+6) in the fixed-point format(1234567.875)

Set precision (setprecision)Used to control the number of the decimal

places to be displayed Showpoint (showpoint)To show value with the decimal point

//demonstrate the output manipulator


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//demonstrate the output manipulator

#include

#include


int main( )

{

char aChar;

int integer;

float dlrAmnt;

cout integer>>dlrAmnt >> aChar;

cout


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THANK YOU!THANK YOU!

MELJUN Intro to C++ Programming

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