The main core of any program is operating on data. When Chapter 2 covered programming, you learned that most programs exist to take data of one kind, process it, and store it as another kind. That processing can take several forms:
Modification: Put this value in this variable.
Comparison: Is this value equal to this value?
The C programming language provides several ways to do this for built-in types; there is a set of keywords and operators that allow you to process them in the language itself. This includes mathematical operators for numerical values, logical operators to test veracity (true or false, Boolean values), and so on.
However, you as the programmer have to provide solutions for user-defined and ...