Insert a new node into a singly linked list a before and b a

Insert a new node into a singly linked list (a) before and (b) after a node pointed to by p in this list (possibly the first or the last). Do not use a loop in either operation.(Answer Using well commented and runable C++ code )

Solution

/* * C++ Program to Implement Singly Linked List */ #include #include #include using namespace std; /* * Node Declaration */ struct node { int info; struct node *next; }*start; /* * Class Declaration */ class single_llist { public: node* create_node(int); void insert_begin(); void insert_pos(); void insert_last(); void delete_pos(); void sort(); void search(); void update(); void reverse(); void display(); single_llist() { start = NULL; } }; /* * Main :contains menu */ main() { int choice, nodes, element, position, i; single_llist sl; start = NULL; while (1) { cout<>choice; switch(choice) { case 1: cout<<\"Inserting Node at Beginning: \"<info = value; temp->next = NULL; return temp; } } /* * Inserting element in beginning */ void single_llist::insert_begin() { int value; cout<<\"Enter the value to be inserted: \"; cin>>value; struct node *temp, *p; temp = create_node(value); if (start == NULL) { start = temp; start->next = NULL; } else { p = start; start = temp; start->next = p; } cout<<\"Element Inserted at beginning\"<>value; struct node *temp, *s; temp = create_node(value); s = start; while (s->next != NULL) { s = s->next; } temp->next = NULL; s->next = temp; cout<<\"Element Inserted at last\"<>value; struct node *temp, *s, *ptr; temp = create_node(value); cout<<\"Enter the postion at which node to be inserted: \"; cin>>pos; int i; s = start; while (s != NULL) { s = s->next; counter++; } if (pos == 1) { if (start == NULL) { start = temp; start->next = NULL; } else { ptr = start; start = temp; start->next = ptr; } } else if (pos > 1 && pos <= counter) { s = start; for (i = 1; i < pos; i++) { ptr = s; s = s->next; } ptr->next = temp; temp->next = s; } else { cout<<\"Positon out of range\"<next;s !=NULL;s = s->next) { if (ptr->info > s->info) { value = ptr->info; ptr->info = s->info; s->info = value; } } ptr = ptr->next; } } /* * Delete element at a given position */ void single_llist::delete_pos() { int pos, i, counter = 0; if (start == NULL) { cout<<\"List is empty\"<>pos; struct node *s, *ptr; s = start; if (pos == 1) { start = s->next; } else { while (s != NULL) { s = s->next; counter++; } if (pos > 0 && pos <= counter) { s = start; for (i = 1;i < pos;i++) { ptr = s; s = s->next; } ptr->next = s->next; } else { cout<<\"Position out of range\"<>pos; cout<<\"Enter the new value: \"; cin>>value; struct node *s, *ptr; s = start; if (pos == 1) { start->info = value; } else { for (i = 0;i < pos - 1;i++) { if (s == NULL) { cout<<\"There are less than \"<next; } s->info = value; } cout<<\"Node Updated\"<>value; struct node *s; s = start; while (s != NULL) { pos++; if (s->info == value) { flag = true; cout<<\"Element \"<next; } if (!flag) cout<<\"Element \"<next == NULL) { return; } ptr1 = start; ptr2 = ptr1->next; ptr3 = ptr2->next; ptr1->next = NULL; ptr2->next = ptr1; while (ptr3 != NULL) { ptr1 = ptr2; ptr2 = ptr3; ptr3 = ptr3->next; ptr2->next = ptr1; } start = ptr2; } /* * Display Elements of a link list */ void single_llist::display() { struct node *temp; if (start == NULL) { cout<<\"The List is Empty\"<info<<\"->\"; temp = temp->next; } cout<<\"NULL\"<