Contoh Program Antrian

Source Code C++:
#include <iostream.h>
#include <conio.h>

int main()
{
    int cek=0, data[20], x, hapus;
    char pil;
    do {
           
           cout<<"1. Tambah Antrian"<<endl;
           cout<<"2. Hapus Antrian"<<endl;
           cout<<"3. Lihat Antrian"<<endl;
           cout<<"4. Keluar"<<endl;
         cout<<endl;
           cout<<"Silahkan masukkan pilihan anda = ";
            pil=getche();
         cout<<endl;
if(pil!='1' && pil !='2' && pil !='3' && pil!='4' )
          cout<<"Andasalah mengetikkan inputan";
            else
            {
               if(pil=='1')   //PUSH
               {
                   if(cek==20)
                       cout<<"Antrian Penuh";
                   else
                   {
                   cout<<"Masukkan nilai = ";
              cin>>x;
                       data[cek]=x;
                       cek++;
                   }
               }
               else
               {
                   if(pil=='2')     //POP
                   {
                       if(cek==0)
                           cout<<"Antrian kosong";
                       else
                       {
                           hapus=data[0];
                           for(int v=0;v<cek;v++)
                               data[v]=data[v+1];
                           data[cek-1]=NULL;
                           cek--;
                      cout<<"Data dengan nilai "<<hapus<<"terhapus";
                       }
                       getch();
                   }
                   else
                   {
                       if(pil=='3')   //CEK DATA
                       {
                           if(cek==0)     
                               cout<<"Antrian Kosong";

                           else
                           {
                               cout<<endl;
                               for(int z=0;z<cek;z++)
                               {
                                   cout<<" | ";
                                   cout<<" "<<data[z];
                                   cout<<" | ";
                               }

                           }
                           getch();
                           return 0;
                       }
                   }
               }
            }

    }while(pil!='4');
}