Paragraphs in a text file

[chantelle89]

I am only a beginner in C. I am trying to find the number of paragraphs in a text file, and so I tried to count the number of empty lines and increment the counter. I searched for ' \n ' in the file and incremented the counter but the program is telling me the number of lines.. not the number of paragraphs. What can I use as a condition in the loop to find empty lines in the file??

[oler1s]

Consider what is an empty line. Let me show you an example:

This is a line.
 
This is another line.
 
This is a third line.
 

Which the computer sees as (represented as text):

This is a line.\n
\n
This is another line.\n
\n
This is a third line.
 

So clearly an empty line has nothing but a newline on it. Your line extraction mechanism probably works by grabbing data until it reaches a newline character. Then it increments a counter of some kind.

You have an empty line when the first thing you grab is a newline itself.

Do you see how to logically look at the problem?

[chantelle89]

Yes thats what my program is doing, grabbing data until it reaches a newline character, then it increments a counter. If only empty lines had a newline character it would work but thats not the case. I can't find anything to put as a condition for detecting an empty line. As you said an empty line has nothing but a newline character on it, so how can you detect an empty line??

[chantelle89]

The only thing I can see is that there is a new paragraph only when there are 2 consecutive newline characters.. Can I use that as a condition?

[Ganon11]

Try it and see if it works.

[oler1s]

The only thing I can see is that there is a new paragraph only when there are 2 consecutive newline characters.. Can I use that as a condition?

If you choose to look at it that way...

You could have 2 consecutive newlines. Or 4. Or 10. Or 100. Or 10000. It doesn't matter. So your code shouldn't be checking for a second newline, because the actual number of consecutive newlines doesn't matter. Because the layout of paragraphs looks something like:

non-newline data.One or more newlines.non-newline data.One or more newlines.non-newline data.One or more newlines.

If your data extraction method makes it easier for you to check consecutive newlines, what you shouldn't be doing is checking repeatedly for additional newlines. There's no point.

Think about it. There's two states your data extraction mechanism can be in. It can be extracting non-newline data. Or it can be extracting newline data. And your paragraph counter increases when you change from extracting non-newline data to extracting newline data.

So you need code that keeps repeatedly extracting non-newline data, checking if it has reached a newline or EOF. Then you increment a paragraph counter when you leave the loop. Then you start looping through the data, until you reach something that isn't a newline (or whitespace technically). You leave the loop when you reach a normal character. Then you go back to looping through normal characters, until you reach a newline or EOF. Then...so on.

One more thing. Are you sure that paragraphs are separated only by a single newline? I would imagine they would be separated by two or more newlines, but not a single newline.

In any case, your approach to the problem depends on how you extract the data. I answered your question assuming you inspected the data character by character.

If you're having trouble understanding the abstract, write it down on paper, and imagine you're the computer inspecting the data. What kind of logic are you following as you extract each character?