Chapter 1 - A Tutorial Introduction 22

Answer to Exercise 1-22, page 34
Solution by Rick Dearman
Write a program to "fold" long input lines into two or more shorter lines after the last non-blank character that occurs before the n -th column of input. Make sure your program does something intelligent with very long lines, and if there are no blanks or tabs before the specified column.

 

Category 1 Solution

 

/******************************************************
   KnR 1-22
   --------
   Write a program that wraps very long lines of input
   into two or more shorter lines.

   Author: Rick Dearman
   email: rick@ricken.demon.co.uk

******************************************************/
#include <stdio.h>

#define MAXLINE 1000 /* max input line size */
   
char line[MAXLINE]; /*current input line*/

int getline(void);  /* taken from the KnR book. */

int
main()
{
  int t,len;
  int location,spaceholder;
  const int FOLDLENGTH=70; /* The max length of a line */

  while (( len = getline()) > 0 )
    {
      if( len < FOLDLENGTH )
 {
 }
      else
 {
 /* if this is an extra long line then we
 ** loop through it replacing a space nearest
 ** to the foldarea with a newline.
 */
   t = 0;
   location = 0;
   while(t<len)
     {
       if(line[t] == ' ')
  spaceholder = t;

       if(location==FOLDLENGTH)
  {
    line[spaceholder] = '\n';
    location = 0;
  }
       location++;
       t++;
     }
 }
      printf ( "%s", line);
    }
  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;

}