solutions/The C Programming Language/1.17.c

#include <stdio.h>

// 80 chars line is too long to test so i shorten to 10
#define MAXLINE 30
#define MAXTEXT 3000
#define SELECTION_LENGTH 10

// output all strings that are longer than MAXLINE

int _getline(char line[], int maxline);
int copy(char to[], int head, char from[]);

main()
{
	int len;
	int longest_lines_head;
	char line[MAXLINE];
	char longest_lines[MAXTEXT];

	longest_lines_head = 0;
	while ((len = _getline(line, MAXLINE)) > 0 && longest_lines_head < MAXTEXT)
		if (len > SELECTION_LENGTH)
		{
			longest_lines_head = copy(longest_lines, longest_lines_head, line);
		}
	printf("%s\n", longest_lines);

	return 0;
}

int _getline(char s[], int lim)
{
	int c, i, j;
	for (i = 0; (c = getchar()) != '\n'; ++i)
	{
		if (i < lim - 1)
			s[i] = c;
	}

	j = i;
	if (j > lim - 1)
		j = lim - 1;
	s[j] = '\0';
	return i;
}

int copy(char to[], int head, char from[])
{
	int from_i;
	int to_i;

	from_i = 0;
	to_i = head;
	while ((to[to_i] = from[from_i]) != '\0' && to_i < MAXTEXT - 1)
	{
		++to_i;
		++from_i;
	}
	to[to_i] = '\n';

	return to_i + 1;
}