Printf problem with Kernighan and Ritchie problem 1-17

Question

In the code below (for problem 1-17 in "The C Programming Language", by Kernighan and Ritchie) why doesn't it print the longest line (at the bottom)?

#include <stdio.h>
#define MAXLINE 1000
#define LONGLINE 10

int getLineLength(char line[], int maxline){
  int i, c;

  for(i = 0; i< maxline-1 && (c = getchar() != EOF) && c != '\n'; i++)
    line[i] = c;

  if(c == '\n') {
      line[i] = c;
      i++;
  }

  line[i] = '\0';
  return i;
}



main() {
  int len;
  char line[MAXLINE];
  while((len = getLineLength(line, MAXLINE)) > 0)
    if(len > LONGLINE)
      printf("The line was over the maxlength\n\t %s", line);

  return 0;
}

Answer 1

In your code:

(c = getchar() != EOF)

This will be evaluated as (c = (getchar() != EOF)), giving the wrong result. What you need is:

((c = getchar()) != EOF)

Answer 2

This program reads from standard input, and prints that long message for lines longer 10 than characters. Lines end with '\n' (newline, ENTER). Input ends with EOF, if you feed a file, e.g. through a pipe, or CTRL-C, if you enter characters manually.

Answer 3

I'm surprised this works at all. (c = getchar() != EOF) is completely wrong for a start. line[i] = c; appears twice. And I think it's vulnerable to a buffer overflow in an edge case.

EDIT: An earlier answer that I can't see any more said that you seem to have your braces missing from the for loop.