A deque (pronounced deck) is an ordered set of items from which item.pdf
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A deque is a double-ended queue that allows insertion and deletion of items at both ends, implemented as a doubly-linked circular list. The document provides code for a deque class in C++, including methods for inserting an element on the right and deleting an element from the left. The example code demonstrates creating two deque instances and performing operations on them.
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A deque (pronounced deck) is an ordered set of items from which item.pdf
- 1. A deque (pronounced deck) is an ordered set of items from which items may be deleted at either end and into which items may be inserted at either end. Call the two ends left and right. This is an access-restricted structure since no insertions or deletions can happen other than at the ends. Implement a deque as a doubly-linked circular list with a header. Write InsertRight and DeleteLeft. Solution code: #include using namespace std; class Node { public: int data; Node* next; Node* prev; }; class Deque { private: Node* front; Node* rear; int count; public: Deque() { front = NULL; rear = NULL; count = 0; } bool isEmpty()
- 2. { if(count == 0) return true; else return false; } int DeleteLeft() { if ( isEmpty() ) { cout<<"deque is empty... can't delete'"; return -1; } int ret = front->data; Node* tmp = front; if ( front->next != NULL ) { front = front->next; front->prev = NULL; } else { front = NULL; } count--; delete tmp; return ret; } void InsertRight(int element) { Node* tmp = new Node(); tmp->data = element; tmp->next = NULL; tmp->prev = NULL; if ( isEmpty() ) { front = rear = tmp; }
- 3. else { rear->next = tmp; tmp->prev = rear; rear = tmp; } count++; } }; int main() { Deque q; if ( q.isEmpty() ) { cout << "Deque is empty" << endl; } q.InsertRight(100); q.InsertRight(200); q.InsertRight(300); Deque q1; if ( q1.isEmpty() ) { cout << "Deque is empty" << endl; } q1.InsertRight(100); q1.InsertRight(200); q1.InsertRight(300); cout << q1.DeleteLeft() << endl; cout << q1.DeleteLeft() << endl; cout << q1.DeleteLeft() << endl; }