An Ethical issue is a problem or issue that requires a person or organization to choose between alternatives that must be evaluated as right (ethical) or wrong (unethical). These issues must be addressed and resolved to have a positive influence in society.
Some of the common ethical issues are listed below:
(i) Cyber crime
(ii) Software Piracy
(iii) Unauthorized Access
(iv) Hacking
(v) Use of computers to commit fraud
(vi) Sabotage in the form of viruses.

A proxy server provides a gateway between users and the internet. It is a server, referred to as an “intermediary” because it goes between end-users and the web pages they visit online. A proxy server is essentially a computer on the internet that has an IP address of its own.

A firewall is a computer network security based system that monitors and controls incoming and outgoing network traffic based on predefined security rules. A firewall commonly establishes a block between a trusted internal computer network and entrusted computer outside the network. They are generally categorized as network-based or host-based. Network based firewalls are positioned on the gateway computers of LANs [local area Network], WANS [Wide Area Network] and intranets.

When a derived class member function has the same name as that of its base class member function, the derived class member function shadows/hides the base class's inherited function. This situation is called function overriding.

Members present in the private visibility mode	Members present in the public visibility mode
Can be accessed only by the class members.	Can be accessed by the outside members also.
By default the members will be in private visibility mode.	Members, to be in public visibility mode has to be specified explicitly.
When classes are inherited, private members are not inherited.	When classes are inherited, the public members are inherited as private, protected and public members of the derived class.

class sale
{
int cost, discount;
public:
sale (sale&);
};
// non inline constructor
sale: : sale(sale&s)
{
cost = s.cost;
discount = s.discount;
}

The term operator overloading, refers to giving additional functionality to the normal C++ operators like +, ++, -, --, +=, -=, *, <, >.It is also a type of polymorphism in which an operator is overloaded to give user defined meaning to it.
For example ¹+'operator can be overloaded to perform addition on various data types, like for Integer, String (concatenation) etc.

Rules for function overloading:
(i) The overloaded function must differ in the number of its arguments or data types.
(ii) The return type of overloaded functions are not considered for overloading same data type.
(iii) The default arguments of overloaded functions are not considered as part of the parameter list in function overloading

(i) Function 1 is the 'destructor'.
It is executed automatically when an object of the class TestMeOut goes out of scope.
(ii) Function 2 is called default 'constructor'.
It is executed automatically when instance of the class TestMeOut comes into scope or when objects of the class TestMeOut are created.

When the initial values are provided during runtime then it is called dynamic initialization.
Example to illustrate dynamic initialization
#include < iostream >
using namespace std;
class X
{
int n;
float avg;
public;
X(int p,float q)
{
n=p;
avg=q;
}
void disp( )
{
cout << "\n Roll number:-"<< n;
cout << "\nAverage:-"<< avg;
}
};
int main( )
{
int a; float b;
cout<< "\nEnter the Roll number";
cin >> a;
cout << "\nEnter the Average";
cin >> b;
X x(a,b);\\dynamic initialization
x.disp( );
return 0;
}
Output:
Enter the Roll Number 1201
Enter the Average 98.6
Roll number:- 1201
Average:- 98.6

Important features of Modular programming:
1. Emphasis on algorithm rather than data
2. Programs are divided into individual modules
3. Each modules are independent of each other and have their own local data
4. Modules can work with its own data as well as with the data passed to it.
Example: Pascal and C.

Paradigm means organizing principle of a program. It is an approach to programming. There are different approaches available for problem solving using computer. They are Procedural programming, Modular Programming and Object Oriented Programming.

(i) A structure variable can be passed to a function in a similar way of passing any argument that is of built-in data type.
(ii) if the structure itself is an argument, then it is called "call by value".
(iii) If the reference of the structure is passed as an argument then it is called, "call by reference".

An array of strings is a two-dimensional character array. The size of the first index (rows) denotes the number of strings and the size of the second index (columns) denotes the maximum length of each string. Usually, array of strings are declared in such a way to accommodate the null character at the end of each string. For example, the 2-D array has the declaration:
char Name[7][10];
In the above declaration,
No. of rows = 7;
No. of columns = 10;
we can store 7 strings each of maximum length 10 characters.

Arithmetic operators perform simple arithmetic operations like addition, substraction, multiplication, division etc.

Unary Operators	Binary Operators
Require only one operand	Require two operands
Example: +,-, *,/,%, >, < <=, AND, OR	Example: ++ (Plus, Plus) Increment operator, --(Minus, Minus) Decrement operator, NOT, -,

Syntax error	Logical error
The syntax is a set of grammatical rules to construct a program. Every programming language has unique rules for constructing the source code. Syntax errors occur when grammatical rules of c++ are violated.	A Program has not produced the expected result even though the program is grammatically correct. It may happen by the wrong use of variable/operator/order of execution etc. This means, the program is grammatically correct, but it contains some logical errors. So, Semantic error is also called as "Logic Error".

Operator	Operation	Result
^	a^b	00001010 a
		00001111 b
		00000101 a^b
a^b = (00000101)2 = 510

1. Case analysis statement generalizes it to multiple cases.
2. Case analysis splits the problem into an exhaustive set of disjoint cases.

De Morgan's
\(\bar { A+B } =\bar { A } .\bar { B } \)
\(\left( \bar { A.B } \right) =\bar { A } +\bar { B } \)

The XNOR (exclusive - NOR) gate is a combination XOR gate followed by an inverter. Its output is "true" if the inputs are the same, and "false" if the inputs are different. 
The output of XNOR is C = AB + \(\bar {A} \) \(\bar {B} \)
= A ⊙ B
where ⊙ indicates included dot.
Truth table

Input		Output
A	B	C
0	0	1
0	1	0
1	0	0
1	1	1

Logic symbol :

S.No	Ubuntu OS	Windows
1.	Open-source (Licensing freedom)	Closed source (Licensing Restriction
2.	Online peer support	Paid-help-desk support
3.	Full hardware support	Partial hardware support
4.	Support CUI	No CUI support
5.	Flexibility	Rigidity

When we open multiple applications, each application opened on the system takes some internal and hardware resources to keep it running. Memory is used by all the applications. System processing speed will be shared and it will become slow finally the system will hang.
Methods of reducing it:
1. It is advisable to run one program at a time.
2. Upgrade RAM
3. Clean the cache Memories
4. Defragmentation can be done

(a) Natural Language Processing
(b) Development of Robotics
(c) Parallel and Distributed computing
(d) Artificial Intelligence
(e) Development of Robotics

Input Device:
It is a peripheral device used to provide data and control signals to an information processing system. Eg: Keyboard, Mouse, Scanners, Digital cameras, Joysticks.

The Basic characteristics of the computers are:
(i) High speed
(ii) Stores Huge Data
(iii) They do millions of different tasks
(iv) Very versatile
(v) Accurate
(vi) Diligence