read line and read three letters at a time in C

Question

I'm having a problem when trying to read 3 letter each time, I want to read line by line and in each line to read sequentially 3 letters at a time.

when read the line when finding the \n jumps to the next line...

i try this

while ((getline(&line, &lenght, file)) != -1){
   while ((strncpy(ch, line, 3)) != NULL) { 

        let = replaceletter(tab, ch);

        if (let != 0)
            printf("%c", let);
   }
}

but it does not work, just read the first 3 letters and I wanted the entire line. I really do not know how to do this, I need help, please

Answer 1

I don't understand how the second while loop is supposed to work. strncpy returns s1, IE ch in this case. ch had better be a char *.

So.. how is ch ever going to == NULL, unless it already was NULL to start off with? And if ch is NULL to start off with (the initialisation of it is not shown) then it's already a segfault :)

It might make sense if this line were

while(*(strncpy(ch, line, 3)) != NULL)) {

HTH