K and R C, Solution to Exercise 6-4:
K and R C Programs Exercises provides the solution to all the exercises in the C Programming Language (2nd Edition). You can learn and solve K&R C Programs Exercise.
Write a C Program that prints the distinct words in its input sorted into decreasing order of frequency of occurrence. Precede each word by its count. Read more about C Programming Language .

/***********************************************************
* You can use all the programs on  www.c-program-example.com
* for personal and learning purposes. For permissions to use the
* programs for commercial purposes,
* contact info@c-program-example.com
* To find more C programs, do visit www.c-program-example.com
* and browse!
* 
*                      Happy Coding
***********************************************************/


#include<stdio.h>
#include<ctype.h>

#define MAXWORD 100
#define NDISTINCT 1000

struct tnode(
  char *word;
int count;
struct tnode *addtree(struct tnode *, char *);
int getword(char *, int);
void sortlist(void);
void treestore(struct tnode *);
struct tnode *list[DISTINCT];
int ntn = 0;

/* print distinct words sorted in decreasing order of freq.*/
main()
{
 struct tnode *root;
 char word[MAXWORD]
           int i;

 root = NULL;
 while(getword(word, MAXWORD) != EOF)
  if(isalpha(word[0]))
   root = addtree(root, word);
 treestore(root);
 sortlist();
 for(i = 0;i < ntn; i++)
  printf("%2d:%20sn",list[i]->count,list[i]->word);
 return 0;
}

//getword: get next word or character from input
int getword(char *word, int lim)
{
 int c, d, comment(void), getch(void);
 void ungetch(int);
 char *w = word;
 while(isspace(c = getch()))
  ;
 if(c !=EOF)
  *w++ = c;
 if(isalpha(c) || c == '-' || c == '#'){
  for(; --lim > 0; w++)
   if(!isalnum(*w = getch()) && *w != '-') {
    ungetch(*w);
    break;
   }
 }
 else if(c == ''' || c == '\'){
  for( ; --lim > 0; w++)
   if(((*w = getch()) == '\')
     *++w = getch();
   else if(*w == c) {
    w++;
    break;
   }else if(*w == EOF)
    break;
 }else if(c == '/')
  if((d = getch()) == '*')
   c = comment();
  else
   ungetch(d);
 *w = '