Sumita Arora Solution

An Expression is any valid combination of operators, literals and variables. for example x + y * (z-3) A statement is instruction given to computer to carry out a specific action. It can be any command with valid literals, variables. for example- x= input(“Enter a String”)

Operators are special symbols which operates data. it determines the type of operation to be done on data. Binary operator example : +, *, ==, > etc.Unary operator example : unary + (Positive), unary – (Negative), ~ (Bitwise Nor) etc.

String literals are represented and implemented by enclosing any text in quotes (either ‘  ‘ or “ “). we can also represent multiline string by enclosing text in triple quotes  “’  ‘”.

floating constants are represented number with decimal points and exponential form. for examplex = 12.89orx=1.28E5

Price*Qty – Invalid class – invalid For – valid do – valid 4thCol – invalid totally – valid Row31 – valid _Amount – valid

Yes, Non graphic characters can be used and processed in python by using backslash ‘ \ ‘ followed by one or more character. for example – ‘\n’, ‘\t’, ‘r’ etc.

Literals are data or value that can be assigned to any identifier and have a fixed value. Python have following literals (1)String Literals (2)Numeric Literals (3)Boolean Literals (4)Special Literals ‘None’

Keyword Identifier System defined word User defined words Always start with lower case Can start with any case Contains only alphabetical characters Can contain alphabets, numbers or underscore

smallest unit of a python program is called token. python has following tokens- (1) Keywords (2) Identifier (3) Literals (4) Operators (5) Punctuators

Advantages: • It is cost effective. • It is easily available. Disadvantages: • There is no guarantee of audio/video quality. • It may not work for emergency service numbers like police or fire services. • It depends upon Internet Protocol.