C++ programs are typically created by linking together one or more OBJ files with one or more libraries. A library is a collection of linkable files that were supplied with your compiler, that you purchased separately, or that you created and compiled. All C++ compilers come with a library of useful functions (or procedures) and classes that you can include in your program. A function is a block of code that performs a service, such as adding two numbers or printing to the screen. A class is a collection of data and related functions; we’ll be talking about classes a lot, starting In Unit 5, "Functions."

The steps to create an executable file are

1. Create a source code file, with a .CPP extention.

2. Compile the source code into a file with the .OBJ extension.

3. Link your OBJ file with any needed libraries to produce an executable program.