Conditions for variables:
Variable names may consist of letters, digits and the underscore character, subject to the following conditions.
- Must consist of only letters, digits and underscores.
- First character must be an alphabet. Some system permits underscore as the first character.
- 31 characters are permitted. But only the first 8 characters are significant.
- Uppercase and lowercase are significant.
- It should not be a keyword.
- White spaces are not allowed.
- Keyword may be a part of the variable. such as , int_type.