Lecture 2 - Lexical Analysis

Question 1

?

is the first phase of a compiler.

WHAT IS LEXICAL ANALYSIS?

Answer 1

Lexical Analysis

Question 2

?

It takes the modified source code from language preprocessors that are written in the form of sentences.

WHAT IS LEXICAL ANALYSIS?

Answer 2

Lexical Analysis

Question 3

Lexical Analysis is the ? of a compiler

Lexical Analysis

WHAT IS LEXICAL ANALYSIS?

Answer 3

first phase

Question 4

It takes the modified source code from ? that are written in the form of sentences.

Lexical Analysis

WHAT IS LEXICAL ANALYSIS?

Answer 4

language preprocessors

Question 5

?

breaks these syntaxes into a series of tokens, by removing any whitespace or commentsin the source code.

WHAT IS LEXICAL ANALYSIS?

Answer 5

Lexical Analyzer

Question 6

If the ? finds a token invalid, it generates an error.

WHAT IS LEXICAL ANALYSIS?

Answer 6

Lexical analyzer

Question 7

?

It reads character streams from the source code, checks for legal tokens, and passes the data to the syntax analyzer when it demands.

WHAT IS LEXICAL ANALYSIS?

Answer 7

Lexical analyzer

Question 8

The Lexical Analyzer breaks these syntaxes into a series of ?, by removing any ?? or comments in the source code.

Lexical analyzer

WHAT IS LEXICAL ANALYSIS?

Answer 8

• tokens
• whitespace

Question 9

If the Lexical analyzer finds a token invalid, it generates an ?.

Lexical analyzer

WHAT IS LEXICAL ANALYSIS?

Answer 9

error

Question 10

It reads character streams from the source code, checks for ?, and passes the data to the ??* when it demands.

Lexical analyzer

WHAT IS LEXICAL ANALYSIS?

Answer 10

• legal tokens
• syntax analyzer

Question 11

?

is a sequence of characters (alphanumeric) in a token.

TOKENS AND LEXEMES

Answer 11

Lexemes

Question 12

?

is a basic abstract unit of meaning.

TOKENS AND LEXEMES

Answer 12

Lexemes

Question 13

?

Lexemes is a sequence of characters (?) in a token.

Lexemes

TOKENS AND LEXEMES

Answer 13

alphanumeric

Question 14

?

There are some predefined rules for every lexeme to be identified as a ?.

Lexemes

TOKENS AND LEXEMES

Answer 14

valid token

Question 15

?

is an object that represents something else.

TOKENS AND LEXEMES

Answer 15

Token

Question 16

?

could be Keywords, Operators, Strings, Constants, Special Symbols, and Identifiers.

TOKENS AND LEXEMES

Answer 16

Tokens

Question 17

?

(6) Tokens and Lexemes

TOKENS AND LEXEMES

Answer 17

• Keywords
• Identifiers
• Constants
• Strings
• Special Symbols
• Operators

Question 18

?

are pre-defined or reserved words in a programming language.

TOKENS AND LEXEMES

Answer 18

Keywords

Question 19

?

Each ? is meant to perform a specific function in a program.

TOKENS AND LEXEMES

Answer 19

Keywords - keyword

Question 20

?

are used as the general terminology for naming of variables, functions and arrays.

TOKENS AND LEXEMES

Answer 20

Identifiers

Question 21

?

their values can not be modified by the program once they are defined.

TOKENS AND LEXEMES

Answer 21

Constants

Question 22

?

refer to fixed values

TOKENS AND LEXEMES

Answer 22

Constants

Question 23

?

They are also called as literals

TOKENS AND LEXEMES

Answer 23

Constants

Question 24

?

is an array of characters ended with a null character.

TOKENS AND LEXEMES

Answer 24

Strings

Question 25

# **?** are always enclosed in double quotes. ## Footnote TOKENS AND LEXEMES

Answer 25

Strings

Question 26

# **?** are used in programming languages having some **special meaning**, thus cannot be used for some other purpose ## Footnote TOKENS AND LEXEMES

Answer 26

Special Symbols

Question 27

# **?** (6) Special Symbols | Special Symbols ## Footnote TOKENS AND LEXEMES

Answer 27

* Brackets * Parentheses * Braces * Comma * Semi colon * Asterisk

Question 28

# **?** used as **array element reference** | Special Symbols ## Footnote TOKENS AND LEXEMES

Answer 28

Brackets

Question 29

# **?** used to indicate **function calls and function parameters.** | Special Symbols ## Footnote TOKENS AND LEXEMES

Answer 29

Parentheses

Question 30

# **?** marks the **start and end of a block of code** containing more than executable statement. | Special Symbols ## Footnote TOKENS AND LEXEMES

Answer 30

Braces

Question 31

# **?** used to **separate more than one statements.** | Special Symbols ## Footnote TOKENS AND LEXEMES

Answer 31

Comma

Question 32

# **?** an operator that essentially **invokes an initialization list.** | Special Symbols ## Footnote TOKENS AND LEXEMES

Answer 32

Semi colon

Question 33

# **?** used to create **pointer variable** | Special Symbols ## Footnote TOKENS AND LEXEMES

Answer 33

Asterisk

Question 34

# **?** are **symbols that triggers an action** when **applied to variables** and other objects. ## Footnote TOKENS AND LEXEMES

Answer 34

Operators

Question 35

# **?** (3) Operators can be classified as follows | Operators ## Footnote TOKENS AND LEXEMES

Answer 35

* Unary Operators * Binary Operators * Ternary Operators

Question 36

# **?** Require only single operand (e.g., increment and decrement). | Operators ## Footnote TOKENS AND LEXEMES

Answer 36

Unary Operators

Question 37

# **?** Require two operands (arithmetic operators, relational operators, logical operators, etc.). | Operators ## Footnote TOKENS AND LEXEMES

Answer 37

Binary Operators

Question 38

# **?** requires three operands (Conditional Operators) | Operators ## Footnote TOKENS AND LEXEMES

Answer 38

Ternary Operators

Question 39

# **?** are the **notations** for describing a **set of character strings.** ## Footnote REGULAR EXPRESSIONS

Answer 39

Regular Expressions

Question 40

# **?** are **used in search engines**, **search and replace dialogs of word processors** and text editors. ## Footnote REGULAR EXPRESSIONS

Answer 40

Regular Expressions

Question 41

# **?** (4) Regular expression (Classification??) ## Footnote REGULAR EXPRESSIONS

Answer 41

1. Any **terminal symbols (e.g. empty and null)** are regular expressions. 2. The **union of two regular expressions** is also a regular expression. 3. The **concatenation of two regular expressions** is also a regular expression. 4. The **iteration or closure of a regular expression** is also a regular expression.

Question 42

# **?** (12) Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 42

* asterisk * plus sign * question mark * backslash * period * caret * square brackets * dollar sign * or sign * curly brackets * parentheses * minus sign

Question 43

# **?** match zero or more quantifier | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 43

asterisk

Question 44

# **?** match one or more quantifier | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 44

plus sign

Question 45

# **?** match zero or one quantifier (makes a preceding character optional) | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 45

question mark

Question 46

# **?** matches any character except the newline symbol | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 46

period

Question 47

# **?** negates the character | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 47

caret

Question 48

# **?** match a single character | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 48

square brackets

Question 49

# **?** anchor for the end of the string | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 49

dollar sign

Question 50

# **?** separates a series of alternatives | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 50

or sign

Question 51

# **?** used as range quantifiers | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 51

curly brackets

Question 52

# **?** used for grouping characters or regular expressions | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 52

Parentheses

Question 53

# **?** indicates a range in a character class | Regular Expression Basics ## Footnote REGULAR EXPRESSIONS

Answer 53

Parentheses