print longest input line;specialized version.

#include <stdio.h>

#define MAXLINE  1000  /*maximum input line size */

int max;               /*maximum length seen so far */
char line[MAXLINE];    /*current input line */
char longest[MAXLINE]; /*longest line saved here */

int getline(void);
void copy(void);

/*print longest input line;specialized version */
main()
{
   int len;
   extern int max;
   extern char longest[];

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

/*getline: specialized version */
int getline(void)
{
   int c, i;
   extern char line[];

  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;
}
/*copy: specialized version */
void copy(void)
{
   int i;
   extern char line[], longest[];

   i = 0;
   while ((longest[i] = line[i]) != '\0')
          ++i;
}