Cs211 module 1_2015

#include<iostream.h>

using namespace std;

int main ( )

{

int r;

float p, peri;

r = 2;

p = 3.14;

peri = 2*p*r;

cout<<―Result is = ―<<peri<<endl;

return 0;

}

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RESULT

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Coding

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Coding

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CS-211 PROGRAMMING

FUNDAMENTALS

Introduction

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Pakistan Air force Schools

F.Sc. PAF Inter college Lahore

B.E. Mechanical Engineering (CEME NUST)

Pak Elektron Limtd. Lahore

Millat Tractors Sheikhupura Road

Descon Lahore

Olayan Descon Saudia

Descon Dubai

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M.Sc. Sustainable Technology, Sweden

Heritage-University of South Asia

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C++ (See plus pluss)

To follow syntax and rules of Turbo C++ and Borland

C+

Text editors e.g. WordPad and note pad

These are used to write the code

Compilers are used to run the code

Source code written and stored in first.cpp

Compiled code stored/saved as first.obj

Executed code stored as first.exe

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Contains following three parts

◦ Preprocessor directives

◦ The main( ) Function

◦ C++ statement

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Preprocessor Directives

Instructions given before beginning of actual program

Also called Compiler Directives

To define certain actions or special instructions (include

arithmetic equation)

Normally begin with number sign (#)

May include keywords like ―include‖ or ―define‖

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Example 1-01

#include<iostream>

int main( )

{

cout <<―this is my first program‖;

return 0;

}

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Example 1-01 (output)

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Preprocessor Directives

Header file

C++ source file

Contains definitions of function/objects

―include‖ is used to add ―iostream‖ into the program

Has Large number of header files in which library

functions are defined

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Example 1-01

#include <iostream>


int main ( )

{


return 0;

}

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Example 1-01


#include<conio.h>

void main( )

{


getch( );

}

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Header file

―iostream‖ is short of ―input output stream‖

Has definitions of several input and output objects or

functions

Which was it in the last example?

―cout‖ (see out)

Syntax

◦ #include <name of the header file>

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Example 1-01

#include<iostream>

int main( )

{


return 0;

}

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The main ( ) Function

Indicates the beginning of a program

After the preprocessor directives

Must be included in every program

Syntax

◦ main ( )

{

program statements…

}

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C++ Statements

Syntax◦ main ( )

{

program statements…

}

The statements are written under main ( )

Between { }

Are the body of the program

Each statement ends with ‗;‘

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C++ Statements

Case sensitivity (must remember)

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C++ Statements

Key words

Words used by languages for

Special purposes

Also called ‗reserved words‘

Cannot be used as variable names

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Example 1-02


int main( )

{

int a, b;

}

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C++ Statements

Tokens

Certain elements of a program

Every thing other than a statement

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Example 1-02

main ( )

{

int a, b;

}

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Example 1-03



int main ( )

{

int abc = 4, b = 1997;

float xy = 3.4;

char name[15] = ―Marriam Ahmed‖;

cout <<name<<endl;

cout<<abc<<endl;

cout<<b<<endl;

cout<<xy<<endl;

return 0;

}

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C++ Statements

Variables

Not a constant

Which may change during execution of a program

Represented by a symbol or a name

Nadeem, fox pro, x, y etc.

It represents a storage location on a computer

Data stored may change, the variable does not

Also known as a object

In C++ variable names consists of alphabets and digits

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C++ Statements

Rules for writing a variable name

First character must be alphabetic, exception ‗_‘

No blank spaces

Arithematic characters not allowed #, ^, etc

Reserved words are not allowed

Maximum length depends up on compiler

Must be declared

Again, case sensitive language

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Variables Valid/Invalid Remarks

Nadeem valid

perform valid

double invalid C++ reserved word

foxpro valid

switch invalid C++ reserved word

Marriam valid

int invalid C++ reserved word

3taq invalid Starts with numeral

unsigned invalid C++ reserved word

x-y invalidSpecial character is not allowed

Taq Ahd invalid Space is not allowed

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Each variable (we define) is specified by the data types of

the data stored in it

Each variable is Declared by its type

C++ has 5 basic data types

◦ int Integer 25, 100, 5000

◦ float Floating Point 3.4×105

◦ double double precision 3.4×105

◦ char characters almost all

◦ bool Boolean logic type variables

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The ‗int‘ Data Type

Represents the integer type data

Integer is a whole number!

i.e. without fraction or decimal◦ 601, 250, -6, 501

The range depends the computer system being used◦ In MS-DOS range is -32768 to 32767

Range can be changed by using following qualifiers◦ short int

◦ long int

◦ unsigned int

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The ‗float‘ Data Type

Represents real or floating type data

Real, decimal or exponential notation

Float, signed or unsigned

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The ‗double‘ Data Type

Represents real or floating type data

Twice the storage capacity than ‗float data type‘

Long double Data type

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The ‗char‘ Data Type

char stands for character

Used to declare character type variables

Variables, alphabetic characters, numeric digits and

special characters can be stored

Twice the storage capacity than ‗float data type‘

Long double Data type

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Declaration of Variables

Assigning the name a variable can hold

◦ Zohaib, sum, addition, x, xyz etc

Assigning the data type a variable can hold

◦ int, float etc

Example

◦ int a;

◦ int abc, xyz, d, s;

Can be more than one variables but separated by a

comma (if of same data type)

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Declaration of Variables

If not, written in each individual line where each

statement is ended with a ‗;‘

Syntax

◦ type list of variables

Example

int a, xy;

Float b;

Char nm [15]

double sum;

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Initialization of Variables

Before we declared a variable

Declared variable gets a memory location assigned to it

that specifies it has a place in memory on the computer

Now a value to the variable must also be assigned or

defined

A known value is assigned to it

◦ int a = 110

The statement can be written as

◦ int a = 110, b = 60, c;

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Example 1-03



int main ( )

{

int abc = 4, b = 1997;

float xy = 3.4;

char name[15] = ―Marriam Ahmed‖;

cout <<name<<endl;

cout<<abc<<endl;

cout<<b<<endl;

cout<<xy<<endl;

return 0;

}

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Constants

A value that cannot be changed during execution of a

program

◦ int a = 44

Four types of constants in C++

◦ Integer constants

◦ Floating point constants

◦ Character constants

◦ String constants

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Constants

Integer constants

Numerical value without a decimal part

+ can also be used with it

Integer constants are used in expressions for calculations

◦ int a = 44, b = 55;

sum = a+b;

cout<<sum<<endl;

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Constants

Floating-point contant

Numeric values having both integer and decimal part

Can also be written in exponential notation

In exponential notation, can be written as

◦ 123.5E2

◦ Where E represents the exponent

both the constant and the E notation can be +

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Example 1-04

#include<iostream>

int main ( )

{

int r;

const float p = 3.14;

float peri;

r = 2;

peri = 2*p*r;

cout<<―Result is = ―<<peri;

return 0;

}

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The ―define‖ Directive

It is a preprocessor directive, used at the beginning of the program

Used to define a constant quantity

Syntax ◦ #define identifier constant

◦ #define p 3.14

Value defined is ‗p‘, where 3.14 is the constant assigned to ‗p‘

3.14 remains same throughout the program

‗p‘ can not be used again in the program to define other

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The ―define‖ Directive

Identifier does not have any data type but any data type

can be assigned to it

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Example 1-05

#include <iostream>

#define p 3.14

int main ( )

{

int r;

float peri;

r = 2;

peri = 2*p*r;

cout<<―Result is = ―<<peri;

return 0;

}

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Arithmetic Operators

Symbols that represent arithmetic operations

Used in arithmetic expressions

Following are the arithmetic operators in C++

Operators Meaning

+ Addition

- Subtraction

* Multiplication

/ Division

% For remainder

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Example 1-06

#include <iostream.h> \\redundant lines will be excluded


int main ( )

{

int d, p, s, m, r;

p = 5+2;

s = 5-2;

m = 5*2;

d = 5/2;

r = 5%2;

cout<<―Addition of 5 & 2 is =―<<p<<endl;

cout<<―Subtraction of 5 & 2 is =―<<s<<endl;

cout<<―multiplication of 5 & 2 is =―<<m<<endl;

cout<<―division of 5&2 is =―<<d<endl;

cout<<―remainder of 5/2 is =―<<r<<endl; }

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Arithmetic Expression

It is a combination of variables, constants and arithmetic

operators

◦ p = m*x+100 where m=10 and x=5

Used to calculate value of an arithmetic formula

Returns a single value after evaluation

Here ‗=‗ is called the assignment operator

After evaluation the resultant variable is called the

―receiving variable‖

◦ res = m*x+100

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Order of Precedence of Operation

It is the order in which the expression is evaluated

C++ only performs one operation at a time

Following is the order of precedence

◦ All multiplications and divisions are performed first from left to

right

◦ All additions and subtractions are then performed left to right

◦ If parenthesis are used in an expression, the expressions within

parentheses are first computed from left to right

◦ When parentheses are used within parentheses, the expression

within innermost parentheses is evaluated first

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Order of Precedence of Operation

Example (4-(3*5))+2 is evaluated as follows

First?

Solution

◦ (3*5) is computed and returns value of 15.

◦ 4-15 is computed and returns value of -11

◦ -11+2 is computed and returns the value of -9

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Statements used to get some data and assign to variables

are input statements

◦ Int a=10, b=510

Statements used to receive data from computer memory

and send to output devices (monitor) are output

statements

◦ cout<<―your total GPA is = ―<<m<<endl;

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The ‗cout‘ object –Output Stream

The flow of data from-and-to a device is called a stream

‗cout‘ (see-out) stands for console out

Here the console out is the display screen (monitor)

‗cout‘ is used as an output statement and is part of

iostream header file

Example

◦ cout<<―One kilobyte = ―<<1024<<―bytes‖;

There are two string constants, one numeric constants

and three put to operators

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Example 1-07

#include <iostream.h>


int main ( )

{

cout<<―one kilobyte = ―<<1024<<―bytes‖;

return 0;

}

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Example 1-08

#include <iostream>

#include <conio> \\used for functions such as

clearing the screen

int main ( )

{

clrscr ( )

cout<<―C++is a powerful programming language‖;

cout<<―UNIX operating system is written in C++‖;

cout<<―it is an easy to learn language‖;

return 0;

}

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Example 1-09

#include <iostream>

int main ( )

{

cout<<―I ‖<<―LOVE ‖<<―PAKISTAN‖ ;

}

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The Escape Sequence

‗endl‘ is similar to an escape sequence

Do you remember what it did?

These are special non-printing characters

Used to control printing on the output device

Combination of ‗\‘ and a code character

For example, \n is an escape sequence which is used to transfer the printing control to a new line

Used inside a string constant or independently

In single or double quotes

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The Escape Sequence

Can be used anywhere in the output stream

for example

◦ cout<<―I Love Pakistan\n‖;

◦ cout<<―I \n Love \n Pakistan‖;

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The Escape Sequence

Escape Sequence Explaination

\a sounds an alert or alarm

\bbackspace, print sequnce moves a space back

cout<<"Pakistan\b";

cout<<"Punjab";

the ouptput will be

PakistaPunjab

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The ―endl‖ Manipulator

Is an important and most common used manipulator

These are the operators used with put to (<<) operators

Stands for end of line

Has the same effect as ―\n‖

For example

◦ cout<<―C++ \n‖<<―programming \n‖<<―language‖;

Is equivalent to

◦ Cout<<―C++ ―<<endl<<―programming ―<<endl<<―language‖;

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Example 1-10

#include <iostream>

int main ( )

{

cout<<―I am a ‖<<endl<<―Pakistani‖ ;

return 0;

}

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Example 1-10

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The ―setw‖ Manipulator

Stands for set width

Used to set width of the output on the output on the

screen

The output is left-justified

Syntax

◦ setw(n) \\where n is the specified width and is an integer

For example

◦ cout<<setw(10)<<―Pakistan‖<<setw(15)<<―Islamabad‖;

Is a part of ―iomanip.h‖ header file

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Result

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Example 1-11

#include <iostream>

#include<iomanip>

int main ( )

{

cout<<setw(5)<<62<<setw(5)<<8<<endl;



return 0;

}

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Example 1-11

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Example 1-12 (Assignment Statement)


int main ( )

{

int a, b, c;

a=200;

b=100;

c=a

a=b

b=c

cout<<―value of a = ―<<a<<endl;

cout<<―value of b = ―<<b<<endl;

}

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Example 1-12

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Example 1-13

#include <iostream>

int main ( )

{

int year, month;

year = 20;

month = year*12;

cout<<―years = ―<<year<<endl;

cout<<―months = ―<<month<<endl;

return 0;

}

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Example 1-13

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The ―cin‖ Object— Input Stream

‗cin‘ (see-in) stands for console input

This is an input stream

It is a part of iostream header file

It requires you to input from your keyboard during the execution of a program

Value is input and press Enter to input the value

Syntax

cin>>var1[>>var2….]; \\ >> is an extraction operator or get from operator

Usually a separate statement is used for each variable

For example ◦ cin>>a>>b>>c; and press Enter to for typing each data

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Example 1-14


int main ( )

{

int n1, n2, s, p;

cout<<―Enter the first number ? ―;

cin>>n1;

cout<<―Enter the second number ? ―;

cin>>n2;

s=n1+n2;

p=n1*n2

cout<<―Sum of numbers = ―<<s<<endl;

cout<<―Product of numbers = ―<<p<<endl;

}

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Example 1-14

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Example 1-15

#include <iostream>

{

int age;

long int age_mon;

char name[50];

cout<<―Enter the name of the person ―;

cin>>name;

cout<<―Enter the age of person in years ―;

cin>>age;

age_mon = age*12;

cout<<―Name of the person = ―<<name<<endl;

cout<<―Age in months = ―<<age_mon<<endl;

}

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Example 1-15

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Example 1-16

float avg;

char name[20];

int total, cpp, os, edp;

cout<<―Enter the name of the student ―;

cin>>name;

cout<<―Enter the marks obtained in C++―;

cin>>cpp;

cout<<―Enter the marks obtained in Operating Systems―;

cin>>os;

cout<<―Enter the marks obtained in EDP―;

cin>>edp;

total = cpp+os+edp;

avg = total/3.0;

cout<<―Name of the student = ―<<name<<endl;

cout<<―Total Marks = ―<<total<<endl;

cout<<―Average Marks = ―<<avg<<endl;

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Example 1-16

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Example 1-17

{

float c, f;

cout << "Enter the temperature in Fahrenheit? ";

cin>>f;

c=(f-32)*5.0/9.0;

cout<<"The temperature in Celsius is = "<<c<<endl;

return 0;

}

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Example 1-17

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Example 1-18

{

float r,h,v;

cout << "Enter the radius of the cylinder = ";

cin>>r;

cout << "Enter the height of the cylinder = ";

cin>>h;

v=3.14*r*r*h;

cout<<"The volume of the cylinder is = "<<v;

return 0;

}

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Example 1-18

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Compound Assignment Statement

We have previously used simple statements, to assign

values to a variable

Like

◦ m=x*100+50

◦ v=p*r*r*h

The same assignment statements can be used to assign

one value to more than one variable.

E.g.

◦ x = y = 16;

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Example 1-19

{

int x, y, a, b, c, s;

x = y = a = b = c = 515;

s = x+y+a+b+c;

cout << "the sum is = " <<s<< endl;

return 0;

}

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Example 1-19

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Compound Assignment Expression

Is used to add, subtract, multiply etc a value to or from a variable ◦ Without writing on either side of op ‗=‗

The arithmetic operator is combined with the assignment operator (=)

Syntax◦ var op = expression

xy = xy + 10;◦ Here 10 is added to the variable xy

◦ Where xy already has some value

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Compound Assignment Expression

Which can also be written as

xy + = 10;

Similarly x += 9; is the same as?

◦ x = x + 9;

x -=9; is the same as?

◦ x = x – 9;

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Example 1-20

{

int a,b,c;

a=3;

b=6;

c=9;

c*=(a+b); // c = c * (a+b)

cout << "Result is = " <<c<< endl;

return 0;

}

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Example 1-20 (cout)

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The Comment Statement

Used to show comment on the coding statements in a

program

Used to explain the logic of the program

It is a non-executable statement

◦ // This is a my first program in C++

◦ // Java language is similar to C++

Can be given in any line of the program

e.g.

◦ sum=a+b //used to take sum of two variables

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Example 1-21

{

// declare the variables

int a,c; //a&c are variable names

a=10; //value 10 is assigned to a

c=a*a*a; //assignment statement to calculate cube

/* next statement is the output statement to

print the cube of 10 */

cout << "cube of "<<a <<" = "<<c<< endl;

// this is the end of the program

return 0;

}

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Example 1-21 (cout)

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