Loss after deletion overlap

[marklove5102]

hash_table.c

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

#define SIZE 5

struct keyval_item {
   int data;   
   int key;
   struct keyval_item* next;
};

struct keyval_item* dataBucket[SIZE] = {NULL}; 

int hashFunc(int key) {
   return key % SIZE;
}

struct keyval_item* search(int key) {
   //get the hash 
   int hashIndex = hashFunc(key);  
   struct keyval_item* head_item = dataBucket[hashIndex]; 

   while(NULL != head_item){
      if(head_item->key == key){
         return head_item;
      }
      head_item = head_item->next;
   }

   return NULL;
}

void insert(int key,int data) {
   struct keyval_item *item = (struct keyval_item*) malloc(sizeof(struct keyval_item));
   item->data = data;  
   item->key = key;

   //get the hash 
   int hashIndex = hashFunc(key);
   if(NULL != dataBucket[hashIndex]){
      // insert before the current and create a new head
      item->next = dataBucket[hashIndex];
   }  
   dataBucket[hashIndex] = item;
}

void delete(struct keyval_item* item) {
   int key = item->key;

   //get the hash 
   int hashIndex = hashFunc(key);
   free(dataBucket[hashIndex]);
   dataBucket[hashIndex] = NULL;    
}

void display() {
   int i = 0;
	
   for(i = 0; i<SIZE; i++) {
      if(dataBucket[i] != NULL){
         printf(" (%d,%d) pair at index = %d\n",dataBucket[i]->key,dataBucket[i]->data, i);
         struct keyval_item* np = dataBucket[i]->next;
         for(; np != NULL; np=np->next)
          printf(" (%d,%d) pair at index = %d\n",np->key,np->data,i);
	 }
   }
	
   printf("\n");
}

int main() {
   

   insert(1, 20);
   insert(2, 70);
   insert(42, 80);
   insert(4, 25);
   insert(12, 44);
   insert(14, 32);
   insert(17, 11);
   insert(13, 78);
   insert(37, 97);
   insert(1, 99);
   display();
   struct keyval_item* item = search(37);
  
   item = search(1);
   if(item != NULL) {
      printf("1Element found: %d\n", item->data);
   } else {
      printf("1Element not found\n");
   }
      item = search(2);
   if(item != NULL) {
      printf("2Element found: %d\n", item->data);
   } else {
      printf("2Element not found\n");
   }
      item = search(4);
   if(item != NULL) {
      printf("4Element found: %d\n", item->data);
   } else {
      printf("4Element not found\n");
   }
      item = search(14);
   if(item != NULL) {
      printf("14Element found: %d\n", item->data);
   } else {
      printf("14Element not found\n");
   }
      item = search(12);
   if(item != NULL) {
      printf("12Element found: %d\n", item->data);
   } else {
      printf("12Element not found\n");
   }
   
         item = search(13);
   if(item != NULL) {
      printf("13Element found: %d\n", item->data);
   } else {
      printf("13Element not found\n");
   }
         item = search(17);
   if(item != NULL) {
      printf("17Element found: %d\n", item->data);
   } else {
      printf("17Element not found\n");
   }
         item = search(42);
   if(item != NULL) {
      printf("42Element found: %d\n", item->data);
   } else {
      printf("42Element not found\n");
   }
   
   if(item != NULL) {
      printf("item Element found: %d\n", item->data);
   } else {
      printf("item Element not found\n");
   }
   item = search(37);
   delete(item);
   item = search(37);

   if(item != NULL) {
      printf("del 37 Element found: %d\n", item->data);
   } else {
      printf("del 37 Element not found\n");
   }
   
   
   item = search(1);
   if(item != NULL) {
      printf("search-1Element found: %d\n", item->data);
   } else {
      printf("search-1Element not found\n");
   }
      item = search(2);
   if(item != NULL) {
      printf("2Element found: %d\n", item->data);
   } else {
      printf("2Element not found\n");
   }
      item = search(4);
   if(item != NULL) {
      printf("4Element found: %d\n", item->data);
   } else {
      printf("4Element not found\n");
   }
      item = search(14);
   if(item != NULL) {
      printf("14Element found: %d\n", item->data);
   } else {
      printf("14Element not found\n");
   }
      item = search(12);
   if(item != NULL) {
      printf("12Element found: %d\n", item->data);
   } else {
      printf("12Element not found\n");
   }
   
         item = search(13);
   if(item != NULL) {
      printf("13Element found: %d\n", item->data);
   } else {
      printf("13Element not found\n");
   }
         item = search(17);
   if(item != NULL) {
      printf("17Element found: %d\n", item->data);
   } else {
      printf("17Element not found\n");
   }
         item = search(42);
   if(item != NULL) {
      printf("42Element found: %d\n", item->data);
   } else {
      printf("42Element not found\n");
   }
}

 (1,99) pair at index = 1
 (1,20) pair at index = 1
 (37,97) pair at index = 2
 (17,11) pair at index = 2
 (12,44) pair at index = 2
 (42,80) pair at index = 2
 (2,70) pair at index = 2
 (13,78) pair at index = 3
 (14,32) pair at index = 4
 (4,25) pair at index = 4

1Element found: 99
2Element found: 70
4Element found: 25
14Element found: 32
12Element found: 44
13Element found: 78
17Element found: 11
42Element found: 80
item Element found: 80
del 37 Element not found
search-1Element found: 99
2Element not found
4Element found: 25
14Element found: 32
12Element not found
13Element found: 78
17Element not found
42Element not found

del 37 = ALL index 2
(37,97) pair at index = 2
(17,11) pair at index = 2
(12,44) pair at index = 2
(42,80) pair at index = 2
(2,70) pair at index = 2