#include <iostream>
using namespace std;

template<class T>
void functionWhichIteratesOverBobs(T &bobs)
{
    int totalAge = 0;
    for(auto &bob: bobs)
    {
         totalAge += bob.age;
    }
}


int main() {
	int i;
	functionWhichIteratesOverBobs(i);  // <--- error
	return 0;
}