Compare Two String using Recursion

#include <iostream>
#include <string>
#include <cstdio>
using namespace std;
bool compare_string(string as, string bs, int i){
    if(as.size() == i) return true;
    if(as.size() != bs.size()) return false;
    if(as[i] != bs[i]) return false;
    compare_string(as, bs, i+1);
}
int main()
{
    string as,bs;
    while(cin>>as>>bs){
        if(compare_string(as, bs, 0)) puts("Same");
        else puts("Not Same");
    }
    return 0;
}