When you create new projects, you should see that there is quite a lot of text that is greyed-out and contains slashes and asterisks. These are called comments and, when you run your program, the compiler will ignore them. Comments are usually nonexecutable statements which are meant for the programmers own convenience.
A comment is usually an explanation regarding the statement. Programmers use comments to allow readers of their code to understand better the code and how it works. Comments consist of English phrases that describe the purpose of the program, the use of identifiers, and the purpose of each program step. It also makes it easier to see where an error might show up.