Thread: defn inside hash table

Good afternoon. I'm studying the hash table program from K&R. I understand name is the content I want to find. But I don't know what is the role of defn in this program.

Code:

 
#include <stdio.h> 
#include <string.h> 

struct nlist { 
    
  struct nlist *next; /* próxima entrada na cadeia */ 
  char *name; /* nome definido */ 
  char *text;     /* texto substituído */

};     

#define HASHSIZE 101

static struct nlist *hashtab[HASHSIZE];

/* hash: create hash value for string s */

unsigned hash(char *s) 
{ 
   unsigned hashval; 
   
   for(hashval = 0; *s != '\0'; s++) 
     hashval = *s + 31 * hashval;
   return hashval % HASHSIZE;      
}

/* lookup: look for s in hashtab */     
struct nlist *lookup(char *s) 
{ 
  struct nlist *np;
  
  for(np = hashtab[hash(s)]; np != NULL; np = np->next)
    if(strcmp(s, np->name) == 0)
      return np; 
  return NULL;         
}     

struct nlist *lookup(char *); 

/* install: put(name, defn) in hashtab */ 

struct nlist *install(char *name, char *defn) 
{ 
   struct nlist *np; 
   unsigned hashval; 
   
   if( (np = lookup(name) ) == NULL) /* not found */ 
   { 
     np = (struct nlist *) malloc(sizeof(*np));  
     if(np == NULL || (np->name = strdup(name)) == NULL)
       return NULL;
     hashval = hash(name);
     np->next = hashtab[hashval];
     hashtab[hashval] = np;  
   }
     else                     
       free((void *) np->defn);
    if((np->defn = strdup(defn)) == NULL)       
      return NULL;
    return np;  
}

char *getword(char *w, int lim) 
{ 
      
}          

int main(void) 
{ 
        
  
   return 0;     
}

Originally Posted by c99tutorial

I think the question is about of terminology:

In other terminology, the NAME part is sometimes called the "key" and the DEFN part is called the "value". So the two together form a single "key-value pair".

Many Thanks. That was what I needed.