c++ introduction, array, pointers included.pptx

HISTORY OF C++
C++ is a multi-paradigm programming language that
supports object oriented programming (OOP)
created by Bjarne Stroustrup in 1983 at Bell
labs, C++ is an extension of C programming and
the programs written in C language can run in C+
+ compiler.
The development of C++ actually began four years
before its release, in 1979. It did not start with the
name C++. Its first name was C with classes.

In the late part of 1983, C with classes was first used for
AT&T’s internal programming needs. Its name was
changed to C++ later in the same year.
It is of course also used in a wide range of other
application domains, notable graphics programming. C++
supports inheritance through class derivation. Dynamic
binding is provided by Virtual class function.

DIFFERENCE BETWEEN C AND C++
C C++
C is Procedural Language. C++ is non-Procedural i.e. Object oriented
Language.
Top down approach is used in Program
Design.
Bottom up approach adopted in Program
Design.
Multiple Declaration of global variables are
allowed.
Multiple Declaration of global variables are
not allowed.
C requires all the variables to be defined at
the starting of a scope.
C++ allows the declaration of variable
anywhere in the scope i.e. at time of its First
use.
In C, malloc () and calloc () Functions are
used for Memory Allocation and free ()
function for memory Deallocating.
In C++, new and delete operators are used
for Memory Allocating and Deallocating.

USES OF C++ LANGUAGE
C++ is used by programmers to develop computer
software
It is used to create general system software
Used to build drivers for various computer devices
Software for servers and software for
specific application.
Used in the creation of video games.

ADVANTAGE OF C++
C++ is relatively-low level and is a systems programming
language.
It has a large community.
It has a relatively clear and mature standard.
Modularity’
Reusability and readability

DISADVANTAGE OF C++
× Data is global or local.
× It emphasis on instructions bur not on data.
× It can be generally heavy if not careful.
× Data is global and global data does not have security.

STANDARD LIBRARIES
The C++ Standard Library can be categories into two
parts:
The standard function library: This library consists of
general-purpose, stand-alone function that are not part of
any class. The function library is inherited from C.
The object oriented class library: This is a collection of
classes and associated function.
Standard C++ library incorporates all the standard C
libraries also, with small additions and changes to
support type safety.

C++ DATA TYPES
Primary data type int, float, char, void
User defined data type structure, union, class, enumeration
Derived data type array, function, pointer, reference

C++ VARIABLES SCOPE
A scope is a region of the program and broadly
speaking there are three places, where variables can
be declared −
Inside a function or a block which is called local
variables,
In the definition of function parameters which is called
formal parameters.
Outside of all functions which is called global
variables.

LOCAL VARIABLES
#include <iostream.h>
int main ()
{
int a, b;
int c;
a = 10;
b = 20;
c = a + b;
cout << c;
return 0;
}
Output
=
?
/actual initialization
// actual initialization

GLOBAL VARIABLES
// Global variable
declaration:
Int g;
int main ()
{
// Local variable
declaration:
int a, b;
// actual initialization
a = 10;
b = 20;
g = a + b;
cout << g;
return 0;
}
Output
=
?
Output =
30

OPERATORS
• Arithmetic operators
• Relational operators
• Logical operators
• Bitwise operators
• Assignment operators

#include<iostream.h>
#include<conio.h>
void main()
{
int a,b,c;
cout<<“enter the
value for a and
b”;
cin>>a>>b;
c=a+b;
cout<<c;
c=a-b;
c=a*b;
cout<<c;
c=a/b;
cout<<c;
c=a++;
cout<<“incrementation of a
by one”<<c;
c=a--;
cout<<”decrementation of a
by one”<<c);
}
ARITHMETIC OPERATORS

#include<conio.h>
void main()
{
int a,b; a=10;b=13;
if(a<b)
{ cout<<“a is less
than b”;
}
if(a>b)
{ cout<<”a is
greater than b”;
}
if(a>=b)
{ cout<<“a is greater than
or equal to b”; }
if(a==b)
{ cout<<”a is equal to b”;}
if(a!=b)
{ cout<<”a is not equal to
b”);
}
}
RELATIONAL OPERATORS

#include<conio.h>
void main()
{
int a,b;
a=12;
b=10;
if(a&&
b)
{ cout
<<”co
ndition
is
a=0;
b=10;
if(a&
&b)
{ cout<<“condition is
true”; } else
cout<<“condition is not
true”;
if(!(a&&b))
{ cout<<“condition is
true”; } }
LOGICAL OPERATORS

BITWISE OPERATOR
Bitwise operator works on bits and perform bit-by-bit operation.
P Q P&Q P|Q P^Q
0 0 0 0 0
0 1 0 1 1
1 0 0 1 1
1 1 1 1 0

Assume if A = 60; and B = 13; now in binary format they will
be as follows:
A = 0011 1100 ----> Binary Number for 60
B = 0000 1101 ----> Binary Number for 13
-----------------
A&B = 0000 1100
A|B = 0011 1101
A^B = 0011 0001
~A = 1100 0011

ASSIGNMENT OPERATOR
An assignment operator, in the context of the C
programming language, is a basic component denoted as
"=".
int x = 25;
x = 50;

FUNCTIONS
Function is a set of statements to perform some task.
 Every C++ program has at least one function, which
is main(), and all the most trivial programs can
define additional functions.
Syntax of Function
return-type function-name (parameters)
{
// function-body
}

DECLARING, DEFINING AND CALLING FUNCTION
#include<iostream.>
int sum (int x, int y); int y
int main()
{
//declaring function
int a = 10;
int b = 20;
int c = sum (a, b); //calling function
cout << c;
}
int sum (int x, int y)
{
//defining function
Output
=
Output
?
= 30
return (x+ y);
}

CALLING A FUNCTION
Functions are called by their names. If the function is
without argument, it can be called directly using
its name. But for functions with arguments, we
have two ways to call them,
Call by Value
Call by Reference

CALL BY VALUE
void swap(int x, int y); // function declaration
int main ()
{
int a = 100;
int b = 200;
cout << "Before swap, value of a :" << a << endl;
cout << "Before swap, value of b :" << b << endl;
swap(a, b); // calling a function to swap the
values.
cout << "After swap, value of a :" << a << endl;
cout << "After swap, value of b :" << b << endl;
return 0; }
// local variable declaration:
OUTPUT:
Before swap, value of a :100
Before swap, value of b :200
After swap, value of a :200
After swap, value of b :100

CALL BY REFERENCE
void swap(int &x, int &y); // function declaration
int main ()
{
int a = 100; int
b = 200;
cout << "Before swap, value of a :" << a << endl;
cout << "Before swap, value of b :" << b << endl;
swap(a, b); // calling a function to swap the values using variable reference.*/
cout << "After swap, value of a :" << a << endl;
cout << "After swap, value of b :" << b << endl;
return 0;
}
// local variable declaration:
OUTPUT:
Before swap, value of a :100
Before swap, value of b :200
After swap, value of a :200
After swap, value of b :100

ARRAYS
 Array is defined as a set of homogeneous data items. An Array
is a group of elements that share a common name that
are differentiated from one another by their positions
within the array.
 It is a data structure which allows a collective name to be
given to a group of elements which all have the same type.
Syntax
datatype arrayname[array size];
 The Array which is declared as above is called single-dimension
array

Example: float salary[10];
float 
salary 
[10]

data type array
name
array
size(integer)
• The size of an array must be an integer
constant and the data type can be any valid
C++ data type.

ARRAY INITIALIZATION
 In C++ elements of an array can be initialized one by one or
using a single statement
float balance[5]={1000.0, 2.0, 3.4,7.0, 50};
 The number of values between braces { } cannot be larger than
the number of elements that we declare for the array
between square brackets [ ].

C++ ARRAY IN DETAIL
CONCEPT DESCRIPTION
Multi-dimensional arrays C++ supports multidimensional arrays. The simplest
form of the multidimensional array is the two-
dimensional array.
Pointer to an array You can generate a pointer to the first element of an
array by simply specifying the array name, without any
index.
Passing arrays to functions You can pass to the function a pointer to an array by
specifying the array's name without an index.
Return array from functions C++ allows a function to return an array.

POINTERS
 Pointer is a user defined data type which creates special types
of variables which can hold the address of primitive data
type like char, int, float, double or user defined data
type like function, pointer etc. or derived data type like
array, structure, union, enum.
What Are Pointers?
 A pointer is a variable whose value is the address of another
variable. Like any variable or constant, you must declare
a pointer before you can work with it.
Syntax
datatype *var-name;

USING POINTERS IN C++
 There are few important operations, which we will do with the
pointers very frequently.
(a) we define a pointer variables
(b) assign the address of a variable to a pointer and
(c) finally access the value at the address available in the
pointer variable.
 This is done by using unary operator * that returns the value of
the variable located at the address specified by its operand.

C++ POINTERS IN DETAIL
CONCEPT DESCRIPTION
C++ Null Pointers C++ supports null pointer, which is a constant with a value
of zero defined in several standard libraries.
C++ pointer arithmetic There are four arithmetic operators that can be used on
pointers: ++, --, +, -
C++ pointers vs. arrays There is a close relationship between pointers and arrays.
C++ array of pointers You can define arrays to hold a number of pointers.
C++ pointer to pointer C++ allows you to have pointer on a pointer and so on.
Passing pointers to functions Passing an argument by reference or by address both
enable the passed argument to be changed in the calling
function by the called function.
Return pointer from functions C++ allows a function to return a pointer to local variable,
static variable and dynamically allocated memory as well.

Why Use Pointers?
• Memory Efficiency: Pointers allow you to manipulate large data
structures without copying them. You can pass pointers to functions
instead of entire arrays or objects.
• Dynamic Memory Allocation: Pointers enable the allocation of
memory during runtime (using new or malloc()), allowing for
flexible memory management.
• Direct Memory Access: Pointers allow for low-level manipulation
of memory, which is useful in system programming, device drivers,
etc.

C++ STRINGS
 The following declaration and initialization create a string
consisting of the word "Hello". To hold the null character at
the end of the array, the size of the character array
containing the string is one more than the number of
characters in the word "Hello.“
 Method 1: char greeting[6] = {'H', 'e', 'l', 'l', 'o', '0'};
 Method 2: char greeting[] = "Hello";

Functions Purpose
strcpy(s1, s2); Copies string s2 into string s1.
strcat(s1, s2); Concatenates string s2 onto the end of string s1.
strlen(s1); Returns the length of string s1.
strcmp(s1, s2); Returns 0 if s1 and s2 are the same; less than 0 if s1<s2;
greater than 0 if s1>s2.
strchr(s1, ch); Returns a pointer to the first occurrence of character ch in string
s1.
strstr(s1, s2); Returns a pointer to the first occurrence of string s2 in string s1.

#include <iostream>
#include <cstring>
int main () {
char str1[10] =
"Hello";
char str2[10] =
"World";
char str3[10];
int len;
strcpy( str
3, str1); //
copy str1
into str3
cout <<
"strcpy( str3,
str1) : " << str3 <<
endl;

FILE HANDLING IN C++
 File Handling concept in C++ language is used for store a data
permanently in computer. Using file handling we can store
our data in Secondary memory (Hard disk).
Why use File Handling
For permanent storage.
The transfer of input - data or output - data from one
computer to another can be easily done by using files.

 For read and write from a file you need another standard C++
library called fstream, which defines three new data types:
Datatype Description
ofstream This is used to create a file and write
data on files
ifstream This is used to read data from files
fstream This is used to both read and write
data from/to files

HOW TO ACHIEVE FILE HANDLING
For achieving file handling in C++ we need follow following steps
 Naming a file
 Opening a file
 Reading data from file
 Writing data into file
 Closing a file

FUNCTIONS USE IN FILE HANDLING
Function Operation
open() To create a file
close() To close an existing file
get() Read a single character from a file
put() write a single character in file.
read() Read data from file
write() Write data into file.

c++ introduction, array, pointers included.pptx

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