averaging using pointers

#include<iostream>
using std::cin;
using std::cout;
#include<conio.h>
void main()
{
int *p,n,a[100],i,j;
float sum=0,avg;
cout<<"enter the no of elements: ";
cin>>n;
cout<<"\nenter the elements-\n";
for(i=0;i<n;i++)
{
cin>>a[i];
}
for(p=&a[0];p<=&a[n-1];p++)
{
sum=sum+*p;
}
avg=sum/n;
cout<<"\nthe average= "<<avg;
getch();
}