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| 1 | +// Iterative C++ program to reverse |
| 2 | +// a linked list |
| 3 | +#include <iostream> |
| 4 | +using namespace std; |
| 5 | + |
| 6 | +/* Link list node */ |
| 7 | +struct Node { |
| 8 | + int data; |
| 9 | + struct Node* next; |
| 10 | + Node(int data) |
| 11 | + { |
| 12 | + this->data = data; |
| 13 | + next = NULL; |
| 14 | + } |
| 15 | +}; |
| 16 | + |
| 17 | +struct LinkedList { |
| 18 | + Node* head; |
| 19 | + LinkedList() { head = NULL; } |
| 20 | + |
| 21 | + /* Function to reverse the linked list */ |
| 22 | + void reverse() |
| 23 | + { |
| 24 | + // Initialize current, previous and |
| 25 | + // next pointers |
| 26 | + Node* current = head; |
| 27 | + Node *prev = NULL, *next = NULL; |
| 28 | + |
| 29 | + while (current != NULL) { |
| 30 | + // Store next |
| 31 | + next = current->next; |
| 32 | + |
| 33 | + // Reverse current node's pointer |
| 34 | + current->next = prev; |
| 35 | + |
| 36 | + // Move pointers one position ahead. |
| 37 | + prev = current; |
| 38 | + current = next; |
| 39 | + } |
| 40 | + head = prev; |
| 41 | + } |
| 42 | + |
| 43 | + /* Function to print linked list */ |
| 44 | + void print() |
| 45 | + { |
| 46 | + struct Node* temp = head; |
| 47 | + while (temp != NULL) { |
| 48 | + cout << temp->data << " "; |
| 49 | + temp = temp->next; |
| 50 | + } |
| 51 | + } |
| 52 | + |
| 53 | + void push(int data) |
| 54 | + { |
| 55 | + Node* temp = new Node(data); |
| 56 | + temp->next = head; |
| 57 | + head = temp; |
| 58 | + } |
| 59 | +}; |
| 60 | + |
| 61 | +int main() |
| 62 | +{ |
| 63 | + /* Start with the empty list */ |
| 64 | + LinkedList ll; |
| 65 | + ll.push(20); |
| 66 | + ll.push(4); |
| 67 | + ll.push(15); |
| 68 | + ll.push(85); |
| 69 | + |
| 70 | + cout << "Given linked list\n"; |
| 71 | + ll.print(); |
| 72 | + |
| 73 | + ll.reverse(); |
| 74 | + |
| 75 | + cout << "\nReversed Linked list \n"; |
| 76 | + ll.print(); |
| 77 | + return 0; |
| 78 | +} |
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