Answer:
#include <iostream>
#include <vector>
using namespace std;
int main() {
vector<int> data;
int num;
cin >> num;
// Read values into vector
while (num >= 0) {
data.push_back(num);
cin >> num;
}
// Check if too many numbers
if (data.size() > 9) {
cout << "Too many numbers";
}
else {
// Print middle item
int mid = data.size() / 2;
cout << "Middle item: " << data.at(mid);
}
return 0;
}