K & R C Programs Exercise 6-3 - C Program Examples

K and R C, Solution to Exercise 6-3:
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.
C Program to Write a cross-referencer program that prints a list of all words in a document, and, for each word, a list of the line numbers on which it occurs. Remove noise words like “the”, “and,” and so on. Read more about C Programming Language .

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/** Write a cross-referencer program that prints a list of all words in a
* document, and, for each word, a list of the line numbers on which it
* occurs. Remove noise words like "the", "and," and so on.
**/

#include 
#include 
#include 
#include 

char *dupstr(char *s) {
 char *p = NULL;
 if(s != NULL){
  p = malloc(strlen(s) + 1);
  if(p) {
   strcpy(p, s);
  }
 }
 return p;
}

int i_strcmp(const char *s, const char *t) {
 int diff = 0;
 char cs = 0;
 char ct = 0;

 while(diff == 0 && *s != '