Static Queue

Insert and Delete operations on a Static Queue :-

#include<iostream.h>
#include<conio.h>
#include<stdlib.h>

const int size =5;
int top=-1,end=-1,a[size];

void push()
 {
      int n;
    if(end==(size-1))
       {
          cout<<"\nOVERFLOW";
            return;
         }
      cout<<"\nEnter an element to add in queue : ";
      cin>>n;
      if(top==-1)
       {
          top=0;
         }
      end++;
      a[end]=n;
      cout<<"\nElement Inserted ";
   }

void pop()
 {
    if(top==-1)
       {
          cout<<"\nUNDERFLOW";
            return;
         }
      else if(top==end)
       {
          top=end=-1;
         }
      for(int i=0;i<=end;i++)
       {
          a[i]=a[i+1];
         }
      if(end>-1)
       { end--; }
   }

void show()
 {
    if(top==-1)
       {
          cout<<"\nQueue is Empty ";
            return;
         }
      cout<<"\nStatus of queue is :- \n";
      for(int i=top;i<=end;i++)
       {
          cout<<" <- "<<a[i];
         }
   }

void main()
 {
    int c;
      while(1)
       {
          cout<<"\n\nPress 1 - to enter element\nPress 2- to delete element\nPress 4 - to exit: \n";
            cin>>c;
            switch(c)
             {
                case 1:
                   push();
                     show();
                     break;
                  case 2:
                   pop();
                     show();
                     break;
                  case 4:
                   exit(0);
                  default:
                   cout<<"\nINVALID OPTION !!\nChoose valid option from given menu....";
                     break;
               }
         }
   }