Character set is the set of characters which are allowed to write a C++ program. A character represents any alphabet, number or any other symbol.

The size of 'x' is 1 character where as the size of "a" is 2 characters.

(i) It is invalid as comma is not allowed in an integer constant.
(ii) It is valid, Comma in bracket is allowed.

Reference variable in C++ is alias for existing variable. They store nothing but the address of the variable used at the time of its declaration. It is important to assign the reference variable at the time of declaration, else it will show an error.

Setw manipulator sets the width of the field assigned for the output. The field width determines the minimum number of characters to be written in output.
Syntax: setw(number of characters)

Operator	Operation	Result
>>	n >> 2	00001010 n = 10
		00001000 n >> 2
		00000010
n >> 2 = (00000010)2 = 210

Keywords are the reserved words which convey specific meaning to the C++ compiler. They are the essential elements to construct C++ programs. Most of the keywords are common to C, C++ and Java. Keywords are reserved and cannot be used as identifiers.

C++ program statements are constructed by many different small elelments such as commands, variables, constants and many more symbols called as operators and punctuators. Individual elements are collectively called as Lexical units or Lexical elements or Tokens. C++ has the following tokens:
(i) Keywords
(ii) Identifiers
(iii) Literals
(iv) Operators
(v) Punctuators

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, -,

C++ program is a collection of functions. Every C++ program must have a main function. The main() function is the starting point where all C++ programs begin their execution. Therefore, the executable statements should be inside the main() function.

Run time error	Syntax Error
1. A run time error occurs during the execution of a program. It occurs because of some illegal operation that takes place. 2. For example, if a program tries to open a file which does not exist, it results in a run-time error.	1. Syntax errors occur when grammatical rules of C++ are violated. 2. Example: if you type as follows, C++ will throw an error. cout << "Welcome to Programming in C++"

Keywords	Identifiers
Keywords are the reserved words which convey specific meaning to the C++ compiler.	Identifiers are the user-defined names given to different parts of the the C++ program.
They are the essential elements to construct C++ programs.	They are the fundamental building blocks of a program.
Most of the keywords are common to C, C++ and Java.	Every language has specific rules for naming the identifiers.

(i) C++ is highly portable language and is often the language of choice for multi-device, multi-platform app development.
(ii) C++ is an object-oriented programming language and includes classes, inheritance, polymorphism, data abstraction and encapsulation.
(iii) C++ has a rich function library
(iv) C++ allows exception handling, and function overloading which are not possible in C.
(v) C++ is a powerful, efficient and fast language. It finds a wide range of applications from GUI applications to 3D graphics for games to real-time mathematical simulations.

(a) a&b 

10	1010
11	1111
a&b	1010

a&b =10₁₀&15₁₀=1010=10₁₀
(b) a|b

10	1	0	1	0
15	1	1	1	1
10 | 15	1	1	1	1

a|b =10|15= 1111₂ =15₁₀
(c) a^b

10	1	0	1	0
15	1	1	1	1
10 ^ 15	0	1	0	1

a^b =10^15= 0101₂ =15₁₀
(d) a>>3
a=10
10/2³=10/8=1
10>>3=1₁₀
(e) (~b)

b	1	1	1	1
~b	0	0	0	0

(~b)=0000₂=0₁₀

Binary Operators require two operands.
Arithmetic operators that perform simple arithmetic operations like addition, subtraction, multiplication, division (+,-*, %,/) etc. are binary operators which requires minimum of two operands.
Relational operators are used to determine the relationship between its operands. The relational operators (<,>,>, <=,=, !=) are applied on two operands, hence they are binary operators.
AND, OR (logical operator) both are binary operators.
Assignment operator is also a binary operator (+=, -=, *=, /=, %=)