C :

#include<stdio.h>
int main()
{   
	double sum;
	int n,i,a[100];
    while(scanf("%d",&n)!=EOF)
	{
		sum=0;
		for(i=0;i<n;i++)
		{
			scanf("%d",&a[i]);
			sum+=a[i];
		}
		printf("%.2lf\n",sum/n);
	}   
	return 0;
}

C++ :

#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
        int n;
        int a[100];
        while (cin>>n&&1<=n&&n<=100)
        {
                int i;
                double sum=0;
                for (i=0;i<n;i++)
                {
                        cin>>a[i];
                        sum+=a[i];
                }
                sum/=i;
                cout<<setiosflags(ios::fixed)<<setprecision(2)<<sum<<endl;
        }
        return 0;
}