Directives

Directives

• They’re not part of the basic C++ language, but they’re necessary anyway.

      Preprocessor Directives
  #include <iostream>

• This is not a program statement or a part of a function body. It starts with a number sign (#). It’s called a preprocessor directive.
• Recall that program statements are instruct-ions to the computer to do something, such as adding two numbers or printing a sentence.
• A preprocessor directive, on the other hand, is an instruction to the compiler. A part of the compiler called the preprocessor deals with these directives before it begins the real compilation process.