Variables

In C variable names must follow specific rules:

• Names can only be composed of upper and lower case letters, numbers, and underscores.
• The first character must be a letter (upper or lower case).
• No keywords are allowed as the full name (int is not allowed but int_count would work).

The main data types in C are: int, float, double, and char.

Variables in C can be initialized with values at their declaration or have their values set later in the code.

In C a variable can be cast explicitly or implicitly from one data type to another. They can then be used directly or stored in another variable.