Checking a character to be a newline

Question

How to check whether a character is a newline character in any encoding in C?

I have a task to write my own wc program. And if I use just if (s[i] == '\n') it has another answer than original wc if I call it to itself.
Here is the code:

typedef struct
{
    int newline;
    int word;
    int byte;
} info;

info count(int descr)
{
    info kol;
    kol.newline = 0;
    kol.word = 0;
    kol.byte = 0;

    int len = 512;
    char s[512];
    int n;

    errno = 0;
    int flag1 = 1;
    int flag2 = 1;
    while(n = read(descr, s, len))
    {
        if(n == -1)
            error("Error while reading.", errno);

        errno = 0; 

        kol.byte+=n;
        for(int i=0; i<n; i++)
        {
            if(flag1)
            {
                kol.newline++;
                flag1 = 0;
            }

            if(isblank(s[i]) || s[i] == '\n')
                flag2 = 1;
            else
            {
                if(flag2)
                {
                    kol.word++;
                    flag2 = 0;
                }
            }
            if(s[i] == '\n')
                flag1 = 1;
        }
    }
    return kol;
}  

It works fine for all text files, but when I call it to file I got after compiling itself it does't give the answer wc gives.

Answer 1

The way to check whether a character s[i] is a newline character is simply:

if (s[i] == '\n')

If you're reading from a file that's been opened in text mode (including stdin), then whatever representation the underlying system uses to mark the end of a line will be translated to a single '\n' character.

You say you're trying to write your own wc program, and by comparing to '\n' you're getting different results than the system's wc. You haven't told us enough to guess why that's happening. Show us your code and tell us exactly what's happening.

You might run into problems if you're reading a file that's encoded differently -- say, trying to read a Unix-format text file on a Windows system. But then wc would have the same problem.