C/C++ Tokens?

C++ Tokens are the smallest individual units of a program.

C++ is the superset of C and so most constructs of C are legal in C++ with their meaning and usage unchanged. So tokens, expressions, and data types are similar to that of C.

Following are the C++ tokens : (most of c++ tokens are basically similar to the C tokens)

• Keywords
• Identifiers
• Constants
• Variables
• Operators

Keywords

Keywords are reserved words which have fixed meaning, and its meaning cannot be changed. The meaning and working of these keywords are already known to the compiler. C++ has more numbers of keyword than C, and those extra ones have special working capabilities.

There are 32 of these, and here they are

auto const double float int short struct unsigned
break continue elseforlong signed switch void
case default enumgoto register sizeof typedef volatile
char do extern if return static unionwhile

There are another 30 reserved words that were not in C, are therefore new to C++, and here they are -

asm dynamic_cast namespace reinterpret_cast try
bool explicit new static_cast typeid
catch false operator template typename
class friend privatethis using
const_cast inline public throw virtual
delete mutable protected true wchar_t

Identifiers

Identifiers are names given to different entries such as variables, structures, and functions. Also, identifier names should have to be unique because these entities are used in the execution of the program.

Identifier naming conventions

• Only alphabetic characters, digits and underscores are permitted.

• First letter must be an alphabet or underscore (_).

• Identifiers are case sensitive.

• Reserved keywords can not be used as an identifier's name.

Constants

Constants are like a variable, except that their value never changes during execution once defined.

There are two other different ways to define constants in C++. These are:

• By using const keyword

• By using #define preprocessor

Declaration of a constant :

const [data_type] [constant_name]=[value];

Variable

A variable is a meaningful name of data storage location in computer memory. When using a variable you refer to memory address of computer.

Syntax to declare a variable

[data_type] [variable_name];

Example

#include <iostream.h>
int main() {
   int a,b;// a and b are integer variable
   cout<<" Enter first number :";
   cin>>a;
   cout<<" Enter the second number:";
   cin>>b;
   int sum;
   sum=a+b;
   cout<<" Sum is : "<<sum <<"\n";
   return 0;
}

Operator

C++ operator is a symbol that is used to perform mathematical or logical manipulations.

• Arithmetic Operators
• Increment and Decrement Operators
• Relational Operators
• Logical Operators
• Bitwise Operators
• Assignment Operators
• Misc Operators

Arithmetic Operators

Increment and Decrement Operators

Relational Operators

Logical Operators

Bitwise Operators

Assignment Operators

Misc Operators