C help required

Hello,
I am making a c program, and i was wondering if anyone knew of a way of counting the number of lines in a text file. I have files with numbers in it, but i dont know how many lines there will be, e.g

23, 23.4, 2.445
756, 5467, 56
...
...

However, I know that each line is termnminated using \n so by counting the number of times that '\n' is written i could find out the total number of rows.

Any ideas?
Thanks.

Quote:

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Originally Posted by rmc

However, I know that each line is termnminated using \n so by counting the number of times that '\n' is written i could find out the total number of rows.

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That is one way; another would be if you are reading the file in line by line (eg with fgets) you could count lines that way.

Thanks for the reply.
Unfortunately im very new to programming, how could you use fgets exactly.
All im doing is storing the data in an array, but i dont know how big to make the array unless i know the number of rows.
???

You use fgets like it says how to in the manual.

i am very sorry for that............my apologies...........i am new to the forum and i dont know how to start a new thread...........please help me in doing so..............i will be very thankful

Quote:

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Originally Posted by rmc

Unfortunately im very new to programming, how could you use fgets exactly.

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You can search the Web, e.g., you might find cppreference.com's entry on fgets.

Quote:

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Originally Posted by rmc

All im doing is storing the data in an array, but i dont know how big to make the array unless i know the number of rows.

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Unfortunately, storing an arbitrary number of lines (using just the C standard library) is probably too advanced for you at the moment. Likewise, storing an arbitrarily long line (using just the C standard library) is also probably to advanced for you at the moment.

If you just use fgets(), you have to assume that the lines have some maximum length. One way to avoid this need for an unknown amount of space is to read character by character, and increment your count whenever you encounter a newline.

Quote:

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Originally Posted by csvraju

i am very sorry for that............my apologies...........i am new to the forum and i dont know how to start a new thread...........please help me in doing so..............i will be very thankful

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tabstop is not trying to be dictatorial (we hope); you should consult some documentation first and then if you have problems using a command, etc. ask for help.

So, in your current circumstance: how are you reading the file who's lines you'd like to count? (ps. before you post code read this)

Well i originally tried it this way, but it doesn't work.

Code:

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while (fscanf(myf,"%*[^\n]\n",&line)!=EOF)
    { 
      sum += line;
    }

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Any ideas why?

That depends on what you mean by "sum", "line", and "doesn't work".

Well, i thought that the sum would be incremented by 1 after each \n, however the sum is not equal to the total number of lines.

It's easier to pinpoint a problem in this procedure if you use fgets() to get a line from the file and sscanf() on the line to extract your data. So for example:

Code:

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char line[64];  /* should be long enough for this, right? */
float data;
FILE *fh;  /* obviously this should be fopend, etc. */
while ((fgets(line,8,8,fh))) {
    sscanf(line, "%f", &data);
}

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The outer layer of brackets is a truth test the same as this:

Code:

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while (fgets(line,8,8,fh)!=NULL) {

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Since fgets returns NULL at end-of-file.

Once you have everything worked out you can always change it back to the straight fscanf().

For counting the lines add this to the loop:

Code:

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sum++;

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Quote:

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Originally Posted by rmc

Well, i thought that the sum would be incremented by 1 after each \n, however the sum is not equal to the total number of lines.

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Why should line be 1? Why wouldn't it be whatever number you read in from the file?
Also, it would get added to after every number, not every line.

So, in your current circumstance: how are you reading the file who's lines you'd like to count? (ps. before you post code read this)[/QUOTE]

Code:

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FILE *fp;
fp = fopen("U:\\data.txt", "rt");

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Quote:

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Originally Posted by rmc

So, in your current circumstance: how are you reading the file who's lines you'd like to count? (ps. before you post code read this)

Code:

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FILE *fp;
fp = fopen("U:\\data.txt", "rt");

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Okay, that's how you open the file. How are you reading the file?

Quote:

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Originally Posted by tabstop

Okay, that's how you open the file. How are you reading the file?

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The OP has admitted to fscanf().