What do you mean by the line'external documentation of your source code'?

Answer 1

An external documentation of your code is a document (probably a file, maybe even a word document) where you list all the methods, variables, etc of your code, you write down what their use is, what are the parameters it takes, what do the variables mean, which are the classes. Basically you explain absolutely EVERY DETAIL about your program so other programmers can refer to it and understand what you did.

Answer 2

An external documentation of your code is a document (probably a file, maybe even a word document) where you list all the methods, variables, etc of your code, you write down what their use is, what are the parameters it takes, what do the variables mean, which are the classes. Basically you explain absolutely EVERY DETAIL about your program so other programmers can refer to it and understand what you did.