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Review of C++ Programming
.
1. What are token? What are different types of tokens used in C++?
Tokens are the basic building blocks of a C++ program. There are five types of tokens in
C++.
1. Key words: Key words are tokens that carry a specific meaning to the language
compiler. Eg. int, switch etc..
2. Identifiers: Identifiers are user defined words that are used to name different program
elements such as memory locations, statements, functions, classes etc.
Identifiers used for naming memory location is known as variables.
Identifiers assigned to statements are known as labels.
Identifiers used for set of statements are known as functions.
3. Literal : Literals are data items that never change their values during the program
running. They are also known as constants. There are 4 types of literals
a) Integer literal: tokens formed only by digits. It must have at least one
digit and must not have decimal point. It may contain +ve or _ve sign as
first character
Eg. 15, -20, +40
b) Floating Point Literal (Real constants): They have fractional part. They
can be written in two forms: Fractional and exponential form.
They have at least one digit and a decimal point. They have either +ve or
–ve sign. In exponential form, there are two parts, Mantissa (Parts
appearing before E) and Exponential(Power).
Eg: 52.15, -715.12, .458E04
c) Character Literal : Single character enclosed with single quotes and that
never changes its value during program run. Non graphical symbols can be
represented by using escape sequence which consists of a back slash(\)
followed by one or more characters. (eg. \n, \a)
Eg. Valid Character Literal: ‘s’, ‘$’,’\n’
Invalid Character Literal: ‘82’, “k”, ‘\8’
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d). String Literals: Sequence of one or more characters enclosed within a
pair of double quotes.
Eg. “computer”. Every string in C++ terminated by a null (\o) character.
4. Punctuators: Special symbols that have syntactic or semantic meaning to the
compiler.
Eg: #, : , ’ , ” ,() ,[]
5. Operators: Operators are the tokens that trigger some kind of operations. The
operations applied on a set of data called operands.
Based on the number of operands, operators are classified into three, Unary operator,
Binary operator and Ternary operator.
A unary operator acts on a single operand. A binary operator acts on two operands. A
ternary operator(? :) acts on three operands.
Based on the nature of operation operators are classified into three Arithmetic,
Relational and Logical operator.
a). Arithmetic operator are used for addition, subtraction, multiplication and division(+,
- , * , / ).
C++ provides a special operator modulus operator(%) for getting remainder of division
operation. For example 10 % 2 returns 0.
b) Relational operators
Relational operators are used to compare values. They produces only ‘True’ of
‘False’ values. The following are the relational operators in C++. c). Logical operator
Logical operators allows us to combine two or more conditions. They are often
referred to as Boolean operators. The logical operators are &&(logical AND),||(logical
OR),and !(logical NOT).
There are some other operators such
as, d). Input-Output operators
The Input-Output operators are used to take input and display output. The
operator(>>) is used for taking input, and the operator(<<) is used to display the output.
The >> operator is called extraction or get from operator. The operator << is called
insertion or put to operator. These are binary operators.
Review of C++ Programming
.
1. What are token? What are different types of tokens used in C++?
Tokens are the basic building blocks of a C++ program. There are five types of tokens in
C++.
1. Key words: Key words are tokens that carry a specific meaning to the language
compiler. Eg. int, switch etc..
2. Identifiers: Identifiers are user defined words that are used to name different program
elements such as memory locations, statements, functions, classes etc.
Identifiers used for naming memory location is known as variables.
Identifiers assigned to statements are known as labels.
Identifiers used for set of statements are known as functions.
3. Literal : Literals are data items that never change their values during the program
running. They are also known as constants. There are 4 types of literals
a) Integer literal: tokens formed only by digits. It must have at least one
digit and must not have decimal point. It may contain +ve or _ve sign as
first character
Eg. 15, -20, +40
b) Floating Point Literal (Real constants): They have fractional part. They
can be written in two forms: Fractional and exponential form.
They have at least one digit and a decimal point. They have either +ve or
–ve sign. In exponential form, there are two parts, Mantissa (Parts
appearing before E) and Exponential(Power).
Eg: 52.15, -715.12, .458E04
c) Character Literal : Single character enclosed with single quotes and that
never changes its value during program run. Non graphical symbols can be
represented by using escape sequence which consists of a back slash(\)
followed by one or more characters. (eg. \n, \a)
Eg. Valid Character Literal: ‘s’, ‘$’,’\n’
Invalid Character Literal: ‘82’, “k”, ‘\8’
, 2
d). String Literals: Sequence of one or more characters enclosed within a
pair of double quotes.
Eg. “computer”. Every string in C++ terminated by a null (\o) character.
4. Punctuators: Special symbols that have syntactic or semantic meaning to the
compiler.
Eg: #, : , ’ , ” ,() ,[]
5. Operators: Operators are the tokens that trigger some kind of operations. The
operations applied on a set of data called operands.
Based on the number of operands, operators are classified into three, Unary operator,
Binary operator and Ternary operator.
A unary operator acts on a single operand. A binary operator acts on two operands. A
ternary operator(? :) acts on three operands.
Based on the nature of operation operators are classified into three Arithmetic,
Relational and Logical operator.
a). Arithmetic operator are used for addition, subtraction, multiplication and division(+,
- , * , / ).
C++ provides a special operator modulus operator(%) for getting remainder of division
operation. For example 10 % 2 returns 0.
b) Relational operators
Relational operators are used to compare values. They produces only ‘True’ of
‘False’ values. The following are the relational operators in C++. c). Logical operator
Logical operators allows us to combine two or more conditions. They are often
referred to as Boolean operators. The logical operators are &&(logical AND),||(logical
OR),and !(logical NOT).
There are some other operators such
as, d). Input-Output operators
The Input-Output operators are used to take input and display output. The
operator(>>) is used for taking input, and the operator(<<) is used to display the output.
The >> operator is called extraction or get from operator. The operator << is called
insertion or put to operator. These are binary operators.
