C++ Identifiers

C++ identifiers are names that identify program elements such as variables using alphabets, numbers, and underscore.

Here is the list of characters for:

• Alphabets:
• Numbers:
• Underscore:

Any other character from your keyboard that does not fall under the above category is called a special character. The uppercase and lowercase are distinct characters. They have different numeric values according to ASCII standard.

There is no limit for the number of characters used as , but some compiler put limitation by recognizing first characters as name. You should read the compiler documentation to get the information.

Rules for Variable Names

The C++ identifiers are used for variable names. We must learn the rules to give valid names to variables. The names must contain allowed characters.

My_var
Table
S
R

The above are some valid names.

5chair
speeed$boat
three dimension

The above three variable names are invalid because:

• variable names cannot begin with a number
• special characters are not allowed
• whitespace is not allowed for variable names.

C++ Keywords

Keywords are special identifiers because they are reserved by the compiler. You cannot use them as variable names and they are case sensitive.

Here is a list of C++ keywords.

Note that sometimes one or more keywords are used together.