1-16.c

/* Exercise 1-16. Revise the main routine of the longest-line program so it will
   correctly print the length of arbitrary long input lines, and as much as
   possible of the text. */

#include <stdio.h>
#define MAXLINE 10 /* maximum input line length */

/* POSIX 1003.1-2008 adds a getline() prototype to stdio.h, conflicting with the
   one below. In such case, rename this function or compile in C89 mode. */
int getline(char line[], int maxline);

void copy(char to[], char from[]);

int main()
{
	int len;	/* current line length */
	int max;	/* maximum length seen so far */
	char line[MAXLINE];	/* current input line */
	char longest[MAXLINE];	/* longest line saved here */
	int c;

	max = 0;
	while ((len = getline(line, MAXLINE)) > 0) {
		if (line[len-1] != '\n')
			while ((c = getchar()) != EOF && c != '\n')
				++len;
		if (len > max) {
			max = len;
			copy(longest, line);
		}
	}
	if (max > 0)	/* there was a line */
		printf("%d: %s\n", max, longest);
	return 0;
}

/* getline: read a line into s, return length */
int getline(char s[], int lim)
{
	int c, i;
	c = '\0';

	for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; ++i)
		s[i] = c;
	if (c == '\n') {
		s[i] = c;
		++i;
	}
	s[i] = '\0';
	return i;
}

/* copy: copy 'from' into 'to'; assume to[] is big enough */
void copy(char to[], char from[])
{
	int i;
	i = 0;
	while ((to[i] = from[i]) != '\0')
		++i;
}