Question

I am implementing hash table in C using linked list chaining method. The program runs, but while searching for an entry, i always get the result "Element is not found" though the element is in hash. This post is a slight edit to my previous post. The program is below:

struct llist{
   char *s;
   struct llist *next;
};

struct llist *a[100];

void hinsert(char *str){
   int strint, hashinp;
   strint = 0;
   hashinp = 0;
   while(*str){
      strint = strint+(*str);
      str=str+1;
   }
   hashinp = (strint%100);
   if(a[hashinp] == NULL){
      struct llist *node;
      node = (struct llist *)malloc(sizeof(struct llist));
      node->s = str;
      node->next = NULL;
      a[hashinp] = node;
   }
   else{
      struct llist *node, *ptr;
      node = (struct llist *)malloc(sizeof(struct llist));
      node->s = str;
      node->next = NULL;
      ptr = a[hashinp];
      while(ptr->next != NULL){
         ptr = ptr->next;
      }
      ptr->next = node;
   }
}  

void hsearch(char *strsrch){
   int strint1, hashinp1;
   strint1 = 0;
   hashinp1 = 0;
   while(*strsrch){
      strint1 = strint1+(*strsrch);
      strsrch = strsrch+1;
   }
   hashinp1 = (strint1%100);
   struct llist *ptr1;
   ptr1 = a[hashinp1];
   while(ptr1 != NULL){
      if(ptr1->s == strsrch){
         cout << "Element Found\n";
         break;
      }else{
         ptr1 = ptr1->next;
      }
   }
   if(ptr1 == NULL){
      cout << "Element Not Found\n";
   }
}  

hinsert() is to insert elements into hash and hsearch is to search an element in the hash. Hash function is written inside hinsert() itself. In the main(), what i am initializing all the elements in a[] to be NULL like this:

for(int i = 0;i < 100; i++){
   a[i] = NULL;
}

Answer 1

You’re not advancing the pointer in this loop. (this is also a really bad hash function)

while(*str){
        strint = strint+(*str);
}