You can NOT use word processing software like Microsoft Word to edit your source code since a source file consists of simple ASCII text, whereas the files created by word processing software have all kinds of other information about the document formatting; they are also usually stored in binary rather than ascii form format.
A source code editor is a piece of software that is designed to help you write your code. Modern source code editors include features that making writing code easier such as syntax highlighting, indentation, autocomplete and brace or bracket matching.
Some of the programming languages we will cover in this course have their own source code editors that are part of an integrated development environment (IDE), while other languages do not have an IDE and thus you need a standalone source code editor.
There are numerous freely available source code editors. Two editors that we recommend are: