Basics of C++

Tokens in C++

In a C++ language, token is either a keyword, a symbol ,an identifier, a constant or a string literal.

A C++ program consists of various tokens for example, the following C++ program consists of four tokens

The individual tokens are −

Comments

Comments are the text in C++  program language and they are ignored by the compiler during compilation and execution.

They start with /* and terminate with the characters */ as shown below −

/* first C ++ program  */

Anything written within Comment will never execute. You can’t write comments within comments.

This is a multi line comment.

We can also use single line comment. 

Single line comment start with // and continue until the end of the line.

Identifiers

In a C++ language, identifier is a name given to any variable, function, or any other user-defined item.

In C++  language identifier starts with a letter A to Z, a to z, digits (0 to 9) or an underscore ‘_’ followed by zero.

C++ language does not allow punctuation characters such as @, $, and % within identifiers.

Here are some examples of acceptable identifiers −

Keywords

In a C++ language keywords are the reserved\predefined words whose meaning already explained in a compiler.

These reserved words can’t be used as a variables or identifier names.

There are 60 key words currently defined for C++.

C++ Keywords
Asm auto bool break case
catch char class const_cast continue
default delete do double else
enum dynamic_cast extern false float
for union unsigned using friend
goto if inline int long
mutable virtual namespace new operator
private protected public register void
reinterpret_cast return short signed sizeof
static static_cast volatile struct switch
template this throw true try
typedef typeid unsigned wchar_t while