c - Deleting in a linked list having many occurences of a value -

1. i using piece of code delete specific value linked list when create linked list having many occurrences of value. , if try delete value goes in infinite loop.

2. but when create linked list distinct values works fine. should do?

my code,

struct link** delete(int value, struct link** head) {     struct link* temp=*head;     struct link* q;     if(head==null)     {         printf("error");     }     else{         while(temp->data!=value){             q=temp;             temp=temp->next;         }         q->next=temp->next;         temp->next=null;         free(temp);         return head;     } } 

your algorithm has numerous problems. including, not limited to...

• dereference temp without checking null. undefined behavior if you're @ end of list , temp falls null.
• there no return value if initial list pointer null.
• dereferencing head before checking null.

and others, but...

use head pointer-to-pointer advantage walk list address-of-links. , done properly, there no need return node pointer. head of list update as-needed if victim value happens occupy first node in list. following code remove all elements in list match specific value. can made considerably more efficient if list known-sorted, now:

void delete(int value, struct link** head) {     if (!head)     {         printf("error");         return;     }      while (*head)     {         if ((*head)->data == value)         {             struct link *tmp = *head;             *head = tmp->next;             free(tmp);         }         else         {             head = &(*head)->next;         }     } } 

that's it. important part of above code not advance pointer-to-pointer head next link in chain if value being removed. instead, joins next value current node (the 1 deleted) resides. once done, target node "orphaned" , can safely delete it. *head automatically references next node test.

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edit: update single-item-removal-only (saw in general-comment)

void delete_one(int value, struct link** head) {     if (!head)     {         printf("error");         return;     }      while (*head && (*head)->data != value)         head = &(*head)->next;      if (*head)     {         struct link *tmp = *head;         *head = tmp->next;         free(tmp);     } } 

best of luck