/* entab: Replaces strings of blanks by the corresponding number of tabs and
   spaces */
#include <stdio.h>

#define MAX_LENGTH 1000

int get_line(char line[]);
void print_line(char line[], int line_length, int tab_length);

int
main()
{
  char line[MAX_LENGTH];
  int line_length;
  int tab_length;

  tab_length = 8;
  while ((line_length = get_line(line)) > 0)
  {
    printf("String with blanks:\n%s", line);
    print_line(line, line_length, tab_length);
  }
  return 0;
}

int
get_line(char line[])
{
  int i;
  char c;

  for (i = 0; i < MAX_LENGTH - 1 &&
              (c = getchar()) != EOF &&
              c != '\n'; i++)
  {
    line[i] = c;
  }

  if (c == '\n')
  {
    line[i] = c;
    i++;
  }

  line[i] = '\0';
  return i;
}

void
print_line(char line[], int line_length, int tab_length)
{
  int i;

  printf("String with tabs/blanks:\n");
  for (i = 0; i < line_length; i++)
  {
    if (line[i] == ' ')
    {
      int j, blank_count;

      for (j = i; line[j] == ' '; j++);
      if (j > i)
      {
        int k, tabs, spaces;

        blank_count = j - i;
        tabs = blank_count / tab_length;
        spaces = blank_count % tab_length;

        for (k = 0; k < tabs; k++, printf("\t"));
        for (k = 0; k < spaces; k++, printf(" "));

        i = j - 1;
      }
      else
      {
        printf("%c", line[i]);
      }
    }
    else
    {
      printf("%c", line[i]);
    }
  }
}