Merge two Sorted Linked List.cpp

SinglyLinkedListNode* mergeLists(SinglyLinkedListNode* head1, SinglyLinkedListNode* head2) {
 SinglyLinkedListNode* result = NULL;  
      
    /* Base cases */
    if (head1 == NULL)  
        return(head2);  
    else if (head2 == NULL)  
        return(head1);  
      
    /* Pick either a or b, and recur */
    if (head1->data <= head2->data)  
    {  
        result = head1;  
        result->next = mergeLists(head1->next, head2);  
    }  
    else
    {  
        result = head2;  
        result->next = mergeLists(head1, head2->next);  
    }  
    return(result);  
}