C++ Character Set

                                C++ Character Set

      Character Set is a set of valid Characters that a language can               recognize.

• Letters  A-Z, a-z
• Digits 0-9
• Special Characters  Space + - * / ^ \  () [] {} = != <> ' " $ , ? _ # <= >= @
• Formatting Characters  Backspace, Horizontal Tab, Vertical Tab, Form Feed,                 Carriage Return.

      White Space Characters

• A character that is used to produce blank space.
• These are spaces, tabs, new lines and comments.

     Tokens: A Token is a group of characters.

      C++ Uses the following types of tokens:-

      *Keyword

        *Identifiers

        *Literals

        *Punctuators

       *Operators

      Identifiers- The Identifier is a sequence of characters taken from C++ character               set.
      The Rules for creation of an Identifier are:

1. An Identifier can consist of alphabets, digits and underscores.
2. It must not start with a digit.
3. C++ is case sensitive.
4. It should not be a reserved word(keyword).

     Keyword-These are some reserved words in C++ which have predefined meanings          to compiler, these words are known as keywords. We can't change the meanings of the          keyword.

    Literals or Constants-A number which does not change its value during                    execution of a program is known as a constant or literals.

     Operator- An operator is a symbol that tells the compiler to perform specific                   mathematical or logical manipulations.

       *Arithmetical Operators

       *Relational Operators 

       *Logical Operators

       *Bitwise Operators 

       *Precedence of Operators

       *Special Operators

       *Escape Operators

     Arithmetical Operators-An Operator that performs an arithmetic operation            such as+,-,*,/ or % is called arithmetic operator.

      Relational Operator

• The Relational Operators are used to test  the relation between two values.
• All Relational Operators are binary operators and require two operands.
• Example  :    ==   !=   >     <    >=     <=

     Logical Operators-It takes true/false value as operands and compute new true/false value.

       Example   &&-Logical AND

       ||- Logical OR

        !- Logical NOT

    Bitwise Operators-Bitwise Operator works on bits and perform bit by bit                    operation.

      Example   &-bitwise AND

      |-bitwise OR

     ^-bitwise exclusive  or(XOR)

     ~-bitwise negation and compliment.

    Special Characters(Increment & Decrement)

• The increment operator (++) adds 1 to its operand and the decrement operator (--) subtracts 1 from its operand.
• x=x+1;is same as x++;
• x=x-1;is the same as x--;
• Both the increment and decrement operator can either precede (prefix) or follow (postfix) the operand.
• x++,x-- Post Increment/Decrement
• ++x,--x Pre Increment/Decrement

   Escape Sequence-An Escape Sequence is represented by  backslash(\) followed          by one more character.