Memoization Using map

#include <iostream>
#include <map>

using namespace std;

map<int, int> fibo;

int fibonacci( int n )
{
        if ( n == 0 || n == 1 ){ return 1; }

        map<int,int>::iterator itr = fibo.find( n );

        if ( itr != fibo.end() )
            return itr->second;
        else
            return fibo[ n ] = fibonacci( n -1 ) + fibonacci( n - 2 );
}
int main()
{
    int n;
    while(cin>>n)
    {
        cout<<fibonacci(n)<<endl;
    }return 0;
}