Read a set of text lines and print the longest.

#include <stdio.h>
#define MAXLINE  1000 /*maximum input line size */

int getline(char line[], int maxline);
void copy(char to[], char from[]);

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

   max = 0;
   while ((len = getline(line, MAXLINE)) > 0)
      if (len > max) {
         max = len;
         copy(longest, line);
      }
   if (max > 0) /* there was a line */
       printf("%s", longest);
   return 0;
}

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

   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;
}