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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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 (output)
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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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Example 1-03 (output)
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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 invalid
Special 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 Pakistann‖;
◦ cout<<―I n Love n Pakistan‖;
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The Escape Sequence
Escape Sequence Explaination
a sounds an alert or alarm
b
backspace, print sequnce moves
a space back
cout<<"Pakistanb";
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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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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Example 1-11
#include <iostream>
#include<iomanip>
int main ( )
{
cout<<setw(5)<<62<<setw(5)<<8<<endl;
return 0;
}
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Example 1-12 (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 1-13
#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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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 1-15
#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 1-16
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 1-17
{
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 1-18
{
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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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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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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Cs211 module 1_2015

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