# include <iostream.h> # include <process.h> # include <conio.h> # include <malloc.h> struct link_list { int no; struct link_list *next; }; class queue { link_list *list,*head; public: queue() { head=NULL; free(list); } void insert(); void display(); void delete_element(); }; void queue :: insert() { link_list *newnode; newnode=new link_list; cout<<\"Enter Number to Insert :\"; cin>>newnode->no; list=head; if(head==NULL) { head=newnode; newnode->next=NULL; } else { newnode->next=list; list=newnode; head=newnode; } } void queue :: display() { cout<<endl; if(head==NULL) { cout<<\"Empty Queue !!!\"; return; } list=head; while(list!=NULL) { cout<<list->no<<\"\\t\"; list=list->next; } } void queue :: delete_element() { cout<<endl; if(head==NULL) { cout<<\"Empty Queue !!!\"; return; } else { list=head; if(list->next==NULL) { cout<<\"Deleted Element : \"<<list->no<<endl; head=NULL; delete(list); list=NULL; return; } while(list->next->next!=NULL) { list=list->next; } cout<<\"Deleted Element : \"<<list->next->no<<endl; delete(list->next); list->next=NULL; } } int display_menu() { int ch; clrscr(); cout<<endl; cout<<\"[ 1 ] Insert\"<<endl; cout<<\"[ 2 ] Delete\"<<endl; cout<<\"[ 3 ] Display\"<<endl; cout<<\"[ 4 ] Exit\"<<endl; cout<<\"Enter your choice :\"; cin>>ch; return ch; } void main() { queue q1; while(1) { switch(display_menu()) { case 1:q1.insert(); break; case 2:q1.delete_element(); getch(); break; case 3:q1.display(); getch(); break; case 4: exit(1); } } }