Variables:
A variable is a data name that may be used to store data value. A variable may take different value at different times during execution. Some examples are, average, height, class_strength.
![](https://1.bp.blogspot.com/-4JPZmroUuDs/VT5k70Bx5JI/AAAAAAAACAg/x3G7AKa9W94/s1600/unnamed.png)
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.