Question

what does mean on a project says Documentation/Diagrams ?

Answer 1

What type of document and graphs to use.

Answer 2

There is documentation of code. For example, describing the variables a function accepts as arguments, their ranges, types etc

Diagrams, you could have flow diagrams to describe how functions call upon one another

Answer 3

Lets say you write a program, nothing huge, just a few thousand lines. Then six months or a year passes and it needs updates because of changes in a DLL. So you go back to your code and try to remember what was doing which part and how it was being used. You scratch your head... then have to learn your own code because you did not document it.

So documenting code saves time later.

Now you work for a company. You are on a team of five programmers. You job is to do certain sub routines that deal with one part of what thew program does. The only way the other people on the team will know what your stuff does is if you document the code.

So documenting code helps you work in teams.

Diagrams are more like a fancy type of documentation where you do a flow chart of program operation. They can be detailed, mapping out decision trees, or more general, mapping out only the overall parts of the program and how they interlock.