Why doesn't my linecount in C work?

Question

I'm trying to read a text file but before that I want to know how many elements I'm going to read. So I need to count the lines of a text file. So far, I have this:

int getLinecount (char *file) 
{
    int ch, count = 0;
    FILE *fp = fopen(file, "r");
    if(fp == NULL)
    {
        return -1;
    }
    while((ch = fgetc(fp)) != EOF)
    {
        if (ch == '\n'); 
        {
            count++;
        }
    }
    fclose(fp);
    return count;
}

This worked pretty fine. I have changed nothing about the text file and still it prints 130,000 though the file only has 10,000 lines. The only thing I wrote in my main is:

linecount = getLinecount("...");

I am really curious where the error is. Also, is there a better option of getting the linecount?

Tracing this through using a debugger would have pointed you to this `;` immediately. — alk, Nov 08 '12 at 15:03
Learn your compiler & compile with full warnings on. For example gcc's `-Wextra` option catches that & outputs: `warning: empty body in an if-statement` — Eugen Constantin Dinca, Nov 08 '12 at 16:12

score 10 · Accepted Answer · answered Nov 08 '12 at 15:01

10

You have a trailing semicolon ; after your if statement. Then, the block is always executed:

{
    count++;
}

answered Nov 08 '12 at 15:01

md5

23,373
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1

How could I overlook that and how did it get there? Thank you so much! – Steffen Nov 08 '12 at 15:04

score 4 · Answer 2 · answered Nov 08 '12 at 15:03

4

Change

if (ch == '\n');

to:

if (ch == '\n')

answered Nov 08 '12 at 15:03

ScoPi

1,193
9
14

score 3 · Answer 3 · answered Nov 08 '12 at 15:01

3

Trailing semi-colon after the if: remove it. With the trailing semi-colon the code is equivalent to:

if (ch == '\n') {}
count++;

meaning that count is incremented for every iteration of the loop (every char in the file).

answered Nov 08 '12 at 15:01

hmjd

120,187
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score 1 · Answer 4 · answered Nov 08 '12 at 15:02

1

you have trailing semicolon to delete after if

and for reading files, better use this code :

while((fgets(blahblahblah)) != NULL) {
  counter++;
}

answered Nov 08 '12 at 15:02

doniyor

36,596
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score 1 · Answer 5 · edited Nov 13 '12 at 11:50

1

Everything is fine except for a semicolon (;), which should be removed from the line

if (ch == '\n')

edited Nov 13 '12 at 11:50

Chris

44,602
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answered Nov 08 '12 at 15:58

Mohit Sehgal

825
1
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score 0 · Answer 6 · edited May 23 '17 at 11:48

0

Apart from the ; issue mentioned by others, an alternative solution can be found in this post as he explains why he does things the way he does.

edited May 23 '17 at 11:48

Community

1
1

answered Nov 08 '12 at 15:04

Jensen

3,498
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score 0 · Answer 7 · edited May 23 '17 at 11:56

0

You might want to consider the OS you are using to create and view this file.

Copied from PHP Echo Line Breaks:

'\n' is a linux/unix line break
'\r' is a classic mac line break [OS X uses the above unix \n]
'\r'+'\n' is a windows line break

edited May 23 '17 at 11:56

Community

1
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answered Nov 08 '12 at 15:06

kdmin

434
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He opens the file in text mode, so the linebreak is '\n' no matter the platform – Daniel Nov 08 '12 at 15:09

Why doesn't my linecount in C work?

7 Answers7