C Program to Remove Duplicate Entries

/* Using Array  */
#include<stdio.h>

int main() {
   int arr[10], i, j, k, size;

   printf("\nEnter array size : ");
   scanf("%d", &size);

   printf("\nAccept Numbers : ");
   for (i = 0; i < size; i++)
      scanf("%d", &arr[i]);

   printf("\nArray with Unique list  : ");
   for (i = 0; i < size; i++)
      {
      for (j = i + 1; j < size;)
        {
         if (arr[j] == arr[i])
            {
            for (k = j; k < size; k++)
                {
               arr[k] = arr[k + 1];
                }
            size--;
            }
         else
            j++;
       }
      }
/*Printing the Result */
   for (i = 0; i < size; i++)
    {
      printf("%d ", arr[i]);
    }

   return (0);
}




/* Using Linked List  */
#include<stdio.h>
#include<stdlib.h>

/* A linked list node */
typedef struct node
{
 int data;
 struct node *next;
} node;

/* Function to remove duplicates from a unsorted linked list */
void rmvDup(node *start)
{
  node *ptr1, *ptr2, *dup;
  ptr1 = start;

  /* Pick elements one by one */
  while(ptr1 != NULL && ptr1->next != NULL)
  {
     ptr2 = ptr1;

     /* Compare the picked element with rest of the elements */
     while(ptr2->next != NULL)
     {
       /* If duplicate then delete it */
       if(ptr1->data == ptr2->next->data)
       {
          dup = ptr2->next;
          ptr2->next = ptr2->next->next;
          free(dup);
       }
       else
       {
          ptr2 = ptr2->next;
       }
     }
     ptr1 = ptr1->next;
  }
}

/* Function to push a node */
void push(node** head_ref, int new_data);

/* Function to print nodes in a given linked list */
void printList(node *node);


int main()
{
  node *start = NULL;

  /* The constructed linked list is:
   10,20,30,20,30,40,50,40 */
  push(&start, 10);
  push(&start, 20);
  push(&start, 30);
  push(&start, 20);
  push(&start, 30);
  push(&start, 40);
  push(&start, 50);
  push(&start, 40);
  printf("\n List of data :  ");
  printList(start);

  rmvDup(start);

  printf("\n\n List after removing duplicates :  ");
  printList(start);

  getchar();
}

/* Function to push a node */
void push(node** head_ref, int new_data)
{
  /* allocate node */
  node* new_node = (node*) malloc(sizeof(node));

  /* put in the data  */
  new_node->data  = new_data;

  /* link the old list off the new node */
  new_node->next = (*head_ref);

  /* move the head to point to the new node */
  (*head_ref)    = new_node;
}

/* Function to print nodes in a given linked list */
void printList(node *node)
{
  while(node != NULL)
  {
    printf("%d ", node->data);
    node = node->next;
  }
}