delete by value

void delete_by_value(int n)
{
    data *temp = head;

    while(temp -> age != n)
    {
        temp = temp -> next;
        if(temp = NULL)break;

    }
    if(temp == NULL)
        return;

    ///Single Node
    if(head == tail){
        free(head);
        head = tail = NULL;
        return;
    }

    ///First Node
    if(temp = head){
        head = temp -> next;
        temp -> next -> prev = NULL;
        free(temp);
        return ;
    }


    ///last node
    if(temp -> next == NULL){
        temp -> prev -> next = NULL;
        tail = temp -> prev;
        free(temp);
        return;
    }


        temp -> prev -> next = temp -> next;
        temp -> next -> prev = temp -> prev;
        free(temp);
}

void rev_print()
{
    data *temp = tail;
    while(temp != NULL){
        printf("%d ",temp -> age);
        temp = temp -> prev;
    }
}