C++ Programming Code Examples C++ > Data Structures Code Examples C++ Program to Implement Doubly Ended Queue C++ Program to Implement Doubly Ended Queue #include <iostream> #include <cstdlib> using namespace std; /* Node Declaration */ struct node { int info; node *next; node *prev; }*head, *tail; /* Class Declaration */ class dqueue { public: int top1, top2; void insert(); void del(); void display(); dqueue() { top1 = 0; top2 = 0; head = NULL; tail = NULL; } }; /* Main: Contains Menu */ int main() { int choice; dqueue dl; while (1) { cout<<"\n-------------"<<endl; cout<<"Operations on Deque"<<endl; cout<<"\n-------------"<<endl; cout<<"1.Insert Element into the Deque"<<endl; cout<<"2.Delete Element from the Deque"<<endl; cout<<"3.Traverse the Deque"<<endl; cout<<"4.Quit"<<endl; cout<<"Enter your Choice: "; cin>>choice; cout<<endl; switch(choice) { case 1: dl.insert(); break; case 2: dl.del(); break; case 3: dl.display(); break; case 4: exit(1); break; default: cout<<"Wrong Choice"<<endl; } } return 0; } /* Insert Element in Doubly Ended Queue */ void dqueue::insert() { struct node *temp; int ch, value; if (top1 + top2 >= 50) { cout<<"Dequeue Overflow"<<endl; return; } if (top1 + top2 == 0) { cout<<"Enter the value to be inserted: "; cin>>value; head = new (struct node); head->info = value; head->next = NULL; head->prev = NULL; tail = head; top1++; cout<<"Element Inserted into empty deque"<<endl; } else { while (1) { cout<<endl; cout<<"1.Insert Element at first"<<endl; cout<<"2.Insert Element at last"<<endl; cout<<"3.Exit"<<endl; cout<<endl; cout<<"Enter Your Choice: "; cin>>ch; cout<<endl; switch(ch) { case 1: cout<<"Enter the value to be inserted: "; cin>>value; temp = new (struct node); temp->info = value; temp->next = head; temp->prev = NULL; head->prev = temp; head = temp; top1++; break; case 2: cout<<"Enter the value to be inserted: "; cin>>value; temp = new (struct node); temp->info = value; temp->next = NULL; temp->prev = tail; tail->next = temp; tail = temp; top2++; break; case 3: return; break; default: cout<<"Wrong Choice"<<endl; } } } } /* Delete Element in Doubly Ended Queue */ void dqueue::del() { if (top1 + top2 <= 0) { cout<<"Deque Underflow"<<endl; return; } int ch; while (1) { cout<<endl; cout<<"1.Delete Element at first"<<endl; cout<<"2.Delete Element at last"<<endl; cout<<"3.Exit"<<endl; cout<<endl; cout<<"Enter Your Choice: "; cin>>ch; cout<<endl; switch(ch) { case 1: head = head->next; head->prev = NULL; top1--; break; case 2: tail = tail->prev; tail->next = NULL; top2--; break; case 3: return; break; default: cout<<"Wrong Choice"<<endl; } } } /* Display Doubly Ended Queue */ void dqueue::display() { struct node *temp; int ch; if (top1 + top2 <= 0) { cout<<"Deque Underflow"<<endl; return; } while (1) { cout<<endl; cout<<"1.Display Deque from Beginning"<<endl; cout<<"2.Display Deque from End"<<endl; cout<<"3.Exit"<<endl; cout<<endl; cout<<"Enter Your Choice: "; cin>>ch; cout<<endl; switch (ch) { case 1: temp = head; cout<<"Deque from Beginning:"<<endl; while (temp != NULL) { cout<<temp->info<<" "; temp = temp->next; } cout<<endl; break; case 2: cout<<"Deque from End:"<<endl; temp = tail; while (temp != NULL) { cout<<temp->info<<" "; temp = temp->prev; } temp = tail; cout<<endl; break; case 3: return; break; default: cout<<"Wrong Choice"<<endl; } } }
