Getting Started & C++ Tokens

 Getting Started

For Execute your C++ Code, You Need a Compiler (Download Now). Source file are Extension with .CPP & Executable File have the .EXE Extension(in Windows). Compiler convert your Source file into execution file By converting your C++ written source code into low level machine code, which made it easy to execute by OS(Operating System).

BEFORE Make your First Program You Must Know Something About Rules of C++ language.


 C++ Character Set

Character set is a set of valid characters that a language can recognize. A character represents any letter, digit  or any other Sign. The C++ has the following character set:

LEtters         A-Z, a-z

Digits           0-9

Special         Space  +  -  * / ^ \ ( ) [ ] { } = != <  >  . ' " $ , ; : % ! & ?
Symbols       _(underscore) # <= >= @

Other Character   C++ can process any of the 256 ASCII characters as data or as Literals

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There is Token(smallest individual unit in a program)
C++ has following TOKEN:

• Keywords
• Identifiers
• Literals
• Punctuators
• Operators

Keywords : These are reserved for special purpose and must not be used as normal identifier  
                    names
                    Followings are C++ KeyWords:

C++ keywords

and and_eq alignas alignof asm auto bitand bitor bool break case catch char char16_t char32_t class compl const constexpr const_cast continue decltype default delete double dynamic_cast else enum explicit export extern false float for friend goto if inline int long mutable namespace new noexcept not not_eq nullptr operator or or_eq private protected public register reinterpret_cast return short signed sizeof static static_assert static_cast struct switch template this thread_local throw true try typedef typeid typename union unsigned using virtual void volatile wchar_t while xor xor_eq

Identifiers : Identifiers are self given name to your Variable, objects , classes, Functions , arrays etc.

Identifiers has some Rules :-

1. An identifier can be combination of letters, numbers, and underscores with following restrictions:

a) It should start with a letter or underscore. E.g. height, my_height,_myHeight are allowed but not 1isGod
b) If it starts with a underscore then the first letter should not be capital because such names are reserved for implementation. E.g. _Height not allowed

2. It should be unique in a program taking care that C++ is case sensitive. E.g. age and Age are different variables

3. A keyword cannot be used as an identifier.

4. There is no restriction on length of the identifier. E.g. h and h_represents_my height are both valid.

Literals: The terms "literal" and "constant" are used interchangeably here. Literals fall into four major categories: integer, character, floating-point, and string literals.

 A literal may be any of the following:

•  Integer-Constant
• Character-Constant
• Floating-Constant
• String-Literal

FOR Example 

157 // integer constant
0xFE // integer constant
'c' // character constant
0.2 // floating constant
0.2E-01 // floating constant
"dog" // string literal

 Punctuators : Punctuators in C++ have syntactic and semantic meaning to the compiler but do not, of themselves, specify an operation that yields a value. Some punctuators, either alone or in combination, can also be C++ operators or be significant to the preprocessor.

Following characters are considered punctuators:

! % ^ & * ( ) – + = { } | ~
[ ] \ ; ' : " < > ? , . / #

Operators: Operators are tokens that trigger some computation when applied to variable and other objects in a expression.

Go to Type of Operators For more Details about operators