How can know if the end of line in C - c

Question

If I do :
int main(){
const int LENGTH_LINE = 100;
char line[LENGTH_LINE];
int len;
FILE* fp = fopen(file.txt,"r");
fgets(line,LENGTH_LINE,fp);
len = strlen(line);
if(line[len-1] == '\n')
printf("I've a line");
//This work if the line have \n , but if the end line of the text dont have \n how can do it?
}
I need to know if I take a whole line with fgets because I got a delimiter.

Answer 1

According to http://en.cppreference.com/w/c/io/fgets
Reads at most count - 1 characters from the given file stream and stores them in str.
Parsing stops if end-of-file occurs or a newline character is found, in which case str will contain that newline character.
So, once fgets returns, there are 3 possibilities
LENGTH_LINE was reached
We got a newline
EOF was reached.
I'm assuming you have a line in cases 2 and 3.
In this case the detection condition is :
line[len-1] == '\n' || feof(fp)

Answer 2

Check for the newline character:
size_t len = 0;
// ... your code using fgets
len = strlen(line);
if ((len > 0) && (line[len - 1] == '\n'))
// your input contains the newline
After the fgets call, your line may not have a newline at the end if:
The character limit was reached before a newline was scanned - in your case this is LENGTH_LINE.
The end-of-file (EOF) was reached before a newline.
There was a read error, but in case of an error consider the contents of line unusable.
You should be looking at the return value from fgets so that you'll be able to handle the EOF: fgets returns NULL upon end-of-file or a read error. You can use feof to check for the end-of-file.
If you check feof, and know that you're at the end of your input with no fgets errors, then even without a newline character on the final line you'll know that you've read the entire line.
If for some reason you must have a newline character terminating each line, you can add it yourself:
// you've checked for EOF and know this is your final line:
len = strlen(line);
if (line[len-1] == '\n')
printf("I've a line");
else if ((len + 1) < LENGTH_LINE)
{
line[len] = '\n';
line[len + 1] = '\0';
}
else
// no room in your line buffer for an add'l character

Answer 3

Use like this
while(fgets(line,LENGTH_LINE,fp)!=EOF)
// your code here

Answer 4

Why not just use fgetc instead? That way you can just keep scanning until you get to the end of the line so you don't have to check if you have it.
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
char line[100];
int ch, i = 0;
FILE* fp = fopen(file.txt,"r");
while(ch != '\n' || ch != '\r' || ch != EOF) //or ch != delimiter
{
ch = fgetc(fp);
line[i] = ch;
i++;
}
line[i] = '\n';
line[i+1] = 0x00;
return 0;
}
In that example I just look for a new line, return, or EOF character but you can really make it look for anything you like (e.g. your delimiter). So if your delimiter was q you would just do
while(ch != 'q')...