صف

#include <iostream.h>
#include <conio.h>
#include <stdlib.h>
class qu{
          public:              //global variable
                   int num;
                   qu *head;
                   qu *tail;
                   qu *sar;
     };
void main()
{
  char cho; qu ali;
       ali.tail = NULL;
asd: clrscr();
       cout<<"enter a number betweeen 1 to 4 for:\n";
       cout<<"1 for enqueu \n2 for dqueue \n3 for show queue\n4 for exit\n";
       cin>>cho;
       qu *newptr = new qu;
       newptr -> tail = NULL;
            if(cho == '1')
                  {
                      if(ali.tail == NULL)
                             {
                                 clrscr();
                                 cout<<"enter your first number: ";
                                 cin>>newptr -> num;
                                 ali.tail = newptr;
                                 ali.sar = newptr;
                                 clrscr();
                             }
                      else
                             {
                                 clrscr();
                                 cout<<"enter other number: ";
                                 ali.tail -> tail = newptr;
                                 ali.tail = newptr;
                                 cin>>newptr -> num;
                              }
                   }

     if(cho == '2')
                {
                      clrscr();
                      qu *dq = new qu;
                      ali.sar = ali.sar -> tail;
                      dq = ali.sar;
                          while(dq)
                                   {
                                          cout<<dq -> num<<" ";
                                          dq = dq -> tail;
                                   }
                     getch();
               }
      if(cho == '3')
              {
                    qu *temp = ali.sar;
                         while(temp)
                               {
                                       cout<<temp -> num<<" ";
                                       temp = temp -> tail;
                               }
                         getch();
              }
      if(cho == '4')
             exit(0);
goto asd;
}