"Just as the mere act of writing in assembler does not of itself guarantee compact, fast code, neither does the use of 'C' in itself guarantee readability, understandability, maintainability, etc, etc. "

I second that.

The two things that make code maintainable is
A solid Design
Meaningful Comments

Even the best comments can not make a bad design understandable and a good design with miserable comments is just as difficult to maintain.

Some programmers believe that the purpose of comments is to describe what the assembler or compiler does such as
mov a,length ;move length into a
anyone needing such a comment should not attempt to read the program in the first place. The purpose of a comment is to describe the intent of (a group of) operation(s). I have learned the hard way how valuable good comments are, in my early days I were thrown a maintenance item for some code I had created two years earlier and I had a time of trying to understand myself.

The most important factor in making a program maintainable is design, design and design many just start coding and end up with a mess that seems to work.

I know that the above is sheer drudgery, but the dividends are enormous.

Have fun,

Erik